Thursday, October 23, 2025

Weather pattern shift continues across southern Quebec

Much needed rainfall this week, along with cooler temperatures has made the outdoors it feel and look more like late October. The fall colours are popping in the Montreal region, with most other areas past peak. Gusty winds this week have removed many leaves form the trees, but some, like this maple on Ile Perrot, remain spectacular. (Valley Weather Photo)

More rain fell in Montreal on Monday evening than in the entire month of September and in October to date. Over 35mm fell in Montreal, alleviating the fire risk and bringing much needed moisture to area waterways.

The pattern change that accompanied the rain will continue, with near or slightly cooler than normal temperatures persisting into next week. An upper level low spinning over the Great Lakes, will slowly drift into southern Quebec and eventually northeast of our region by the weekend. Expect the weather to be like, well, October for the next few days. Stubborn clouds, along with gusty west winds, will keep temperatures around 10C (50F) into Saturday. A few isolated showers are possible, especially during the afternoon hours.

Locations closer to the Great Lakes and St. Lawrence Valley have the higher risk of seeing those showers. Overnight lows will drop into the single digits. Cold temperatures are expected in the Eastern Townships and higher elevations of upstate New York and Vermont, where a few snowflakes are possible on Friday evening. At this time, there is no snow in the forecast for Montreal.

High pressure will try to clear the skies out in Montreal by Saturday afternoon into Sunday, but clouds and precipitation are expected to return early next week. Temperatures will remain on the cool side of normal through the forecast period.

National Hurricane Center forecast track of Tropical storm Melissa. The storm is expected to strengthen into a major hurricane this weekend, threatening Jamaica. (NOAA/NHC)

Tropical Storm Melissa

While this year's hurricane season has been active, the majority of the storms have remained out over the open waters of the Atlantic Ocean. Melissa may become a serious problem as early as this weekend. The tropical storm is located early Thursday morning 345 kilometres southeast of Kingston, Jamaica. The storm is meandering around the Caribbean Sea, drifting northwest at 7km/h. Wind shear is keeping the storm rather disorganized and in check, but that is expected to change.

Forecasters at the National Hurricane Center expect Melissa to become a major hurricane this weekend, with potential catastrophic impacts for Jamaica, Haiti and parts of Cuba. Steering currents are very weak at this time, as a result the forecast is subject to change. At this time, dangerous flooding and mudslides are possible over Haiti, Jamaica and the Dominican Republic. Rainfall amounts may exceed 250mm through Friday.

Winds, waves and storm surge are forecast to increase through Saturday along the southern coasts of all three countries as well as Cuba and the Cayman Islands. A hurricane watch in in effect for the region.

Monday, October 20, 2025

October weather set to return to Montreal this week

Summer in October. Hazy sunshine along the banks of the St. Lawrence River on Sunday afternoon, as temperatures soared into the 20s. Low water levels have created a new beach on Ile Perrot. Thankfully rain is forecast this week. (Valley Weather Photo)

Much needed rainfall and cooler weather on the way for southern Quebec this week.

The summery, fall weather was nice while it lasted, but the end is just a few hours away. Rain is on our doorstep Monday morning as low pressure moves north of Montreal trailing a slow moving, potent cold front behind it. That will establish a pattern change, at least for the week ahead and perhaps beyond.

Our weather has been unseasonably warm and dry, the warmest coming on Sunday, when the mercury hit 22.3C (73F) at Trudeau Airport. That was well-above the normal high for mid-October of 11C (52F), and just shy of the record high for the date of 24.7C (76F) set in 2007 Saint Anicet and Cornwall, Ontario were the warmest locations in the country Sunday, approaching a remarkable 28C (83F). 

Strong southerly winds gusted as high as 70km/h across the region. This combined with low relative humidity values and our ongoing drought, resulted in several wildfires igniting. One such fire burned 4.5 hectares near Chemin Lac St-Louis in the South Shore community of Lery. I watched from Pointe-du-Moulin on Ile Perrot as a provincial water bomber doused the fire, bringing it quickly under control, with the help of firefighters on the ground.

A Canadair CL-415 Super Scooper prepares to drop water on a wildfire burning near Lery on the South Shore Sunday afternoon. Tinder dry conditions, warm temperatures and strong winds helped spread the fire over at least 4.5 hectares. Other fires were reported in eastern Ontario and upstate New York. (CTV NEWS/Corey Wilson)

The tinder dry conditions also sparked other fires around eastern Ontario, upstate New York and southwestern Quebec. Burn bans have been in place for several weeks now, but despite this, most of the fires so far this year have been caused by campfires or open burning of debris and vegetation.

I was amazed by how low the water level is on the Saint Lawrence River, despite the release of water this weekend from the Moses-Saunders Dam near Cornwall on Saturday. We now have a beach on Ile Perrot, beautiful fpr a Sunday afternoon walk, but water levels are too low.

RAIN... FINALLY!

The good news is we have a much cooler and moist airmass on the way for this week. Rain and thunderstorms are forecast fro Monday, with as much as 25mm expected. The showery weather will persist all week, as an upper level low settles over the region. We may have 25-50mm of rain by Friday, easily surpassing the total so far this moth, that is stuck at 22.4mm for Montreal. 

This will be real October weather for a change, as temperatures settle back down into the low teens for highs and around 4C (39F) for lows by midweek. The cooler, damp weather will persist into next weekend, with even the risk of a few snowflakes over the higher elevations north and southeast of the city by Thursday into Friday.

Friday, October 17, 2025

Warmer weekend - much needed moisture on the way for Montreal

My annual photo showing the date of the first frost of the season on Ile Perrot. Most locations across southern Quebec have now reported frost, with the growing season winding down. (Valley Weather)

Strong high pressure has led to a frosty morning Friday, in Montreal, with temperatures dropping close to the freezing point at many locations. Most locations off island have already had the first frost of the season, so while a frost advisory will likely be posted Friday night as well, the growing season is coming to an end.

Precipitation remains at a premium in southern Quebec this month as it has most of the summer an early fall. To date, only 22.4mm of rain has fallen at Trudeau Airport, falling on two days this month, Drought conditions remain severe to extreme across a wide area from central and southern Ontario across the St. Lawrence Valley and into northern New England.

While the fall weather this year has been spectacular, we desperately need rain. Only 22mm has fallen at Trudeau Airport in October, with large parts of the region reporting severe to extreme drought conditions. The wildfire risk remains very high to extreme with outdoor burning prohibited or strongly discouraged for most parts of southwestern Quebec. (Valley Weather)

High pressure will remain in control of our weather through the upcoming weekend, but there is some good news on the horizon as far as rainfall is concerned. Temperatures will warm over the weekend, from cool daytime highs of 13C (55F) Friday, to near-summer warmth Sunday at 22C (72F). Gusty southwest winds are expected Sunday, in advance of a cold front that will usher in a pattern change next week.

Two areas of low pressure will pass north of Montreal next week, dragging several frontal boundaries across southern Quebec. Clouds and showers wil prevail for a good portion of the week, with estimates of 25-50mm (1-2 inches) of rain for the week. Temperatures will trend cooler as well, with highs dropping into the lower teens.

An aerial view of severe flooding in the village of Kotzebue, Alaska after the passage of what was left of Typhoon Halong. Thousands are homeless and damage is significant in many villages across the western part of the state. (Alaska Department of Transportation and Public Facilities Photo)

Active Weather Week

It has been a very active weather week across many parts of NorthAmerica, despite our quiet weather here in Montreal. A strong Nor'Easter last weekend remained largely south of Montreal, producing widespread coastal flooding from North Carolina to Long Island. Homes were inundated and roads washed away. Thousands were left without power from New Jersey to North Carolina.

Meanwhile in western Canada, a strong fall storm produced the first significant snowfall of the season across parts of southern Alberta and Saskatchewan on Thanksgiving Day. Travel was extremely difficult, especially in Alberta. Some locations reported over 10cm of fresh snow, along with wind gusts over 80km/h.

In Alaska, the remains of Typhoon Halong produced strong winds, heavy rain and a devastating storm surge resulting in catastrophic flooding. Several homes were washed away, leading to the evacuation of over 1500 residents. Several villages in the western part of the state were flooded with homes washing out to sea. One death has been reported so far.

Thursday, October 09, 2025

Frost advisory for southern Quebec - drought lingers

FALL RETURNS: The record heat in Montreal Sunday and Monday, came to a quick end on Tuesday as a strong cold front crossed the Montreal region. Temperatures dropped to more seasonable values along with the first rain for October, 19mm in Montreal. Temperatures dropped form the record high of 29C (85F) Monday, to 22C (72F) Tuesday, and 17C (63F) Wednesday. Frost is likely Thursday night. (Valley Weather Photo)

Frost Advisory for Montreal

What may have been our last really warm weather of the season came to an abrupt end Tuesday along a strong cold front. That front brought the first rain for the month of October to Montreal, with a general 15-20mm falling across southern Quebec. For the short-term, the ban on open fires has been lifted for the Montreal region, but it remains in effect for other parts of western Quebec. The wildfire risk remains extreme for many, with much more rainfall needed to alleviate the drought conditions and tinder dry forests. If at all possible, just avoid any campfires, fire pits or fireworks all together.

There is no rain in the forecast through at least Sunday. The cooler temperatures that have settled into our region will allow for some frost to develop by Friday morning. A frost advisory is in effect. While Thursday morning was chilly, with lows close to the freezing point, gusty northwest winds kept the risk for frost minimal in the city.

Thursday will be a sunny, cool day, with highs only reaching the low teens. Overnight into Friday, clear skies and calm winds will allow for lows close to 0C (32F) and perhaps our first real frost for most of the region around metro Montreal.

High pressure will be in control of our weather through Sunday, with fair weather and moderating temperatures, into the upper teens for highs and upper single digits for lows. Some shoers may develop Thanksgiving Monday on the far northern edge of a strong Nor'easter coastal storm. That storm is expected to produce very heavy rainfall, strong winds up to 100km/h and pounding surf along the middle Atlantic and northeast coastlines. Montreal may see some clouds and showers along the extreme northern edge of the storm.

A home falls into the Atlantic Ocean in Buxton, North Carolina. The Outer Banks have been pounded by serval major storms this year, with another forecast this weekend. (National Park Service Photo)

First Nor'easter of the fall season

For those of you who read my blog and a regular basis, you will know that I vacation often on the Outer Banks of North Carolina, specifically Hatteras Island. That region has been taking a beating this summer, with several major hurricanes passing well offshore but delivering towering waves and surf. The result has been significant beach erosion, with infrastructure, roads and homes falling victim to the Atlantic Ocean. Just last week, at least 9 homes fell into the surf in Buxton and Rodanthe. 

The news of another significant coastal storm on the heels of hurricanes Humberto and Imelda is not welcome for the residents and tourists of the region. According to the National Park Service that manages the beaches, the value of the homes alone lost last week alone was placed at more than $5 million dollars, with  a very costly cleanup underway.

Monday, October 06, 2025

Warmest October day on record for Montreal

It certainly looked like Autumn on Sunday, but it did not feel like it at all. Temperatures soared into the upper 20s for many locations, with several all-time October record highs falling, including in Montreal and Burlington, Vermont. Dozens of new records were established for the date. Monday will be another warm and dry day, with extreme wildfire conditions forecast. Avoid all outdoor burning, including campfires. (Valley Weather Photo)

The warm and dry weather continues across southern Quebec and Ontario Monday after several all-time October records were established on Sunday. Montreal's Trudeau Airport reached 29.9C (85F), a new record for the date and month, surpassing the daily high of 28.5C (83F) set in 2023, and the all-time monthly high of 29.3C (84F) set on October 1st, 2023. The normal high for October 5, is 14C (56F).

Strong high pressure has been in control of the weather across southern Quebec since late September, with no rainfall at all so far in October. This follows a near-record dry month for September, with only 33mm falling in Montreal. The danger for wildfires remains extreme across southern Quebec, with the ban for outdoor fires now extending to all parts of the region including metro Montreal according to SOPFEU.

The fire risk will only increase Monday, with another record warm day forecast, with a high of 28C (83F) for Montreal. The previous record for the date is 26C (79F) set in 2005. In addition to the hot weather, we can expect gusty southwest winds to increase to 20 to 40km/h, along with very low relative humidity levels in the afternoon. Any potential wildfires would spread quickly in these conditions. It is critical that you avoid all outdoor burning today and Tuesday, including campfires.

Despite the vibrant foliage and Halloween decorations, Sunday felt more like August in Montreal and not October, with blazing sunshine and record high temperatures observed.

The dry weather this fall has increased the amount of fires burning in Quebec, with 28 reported as of Monday morning. This includes one that started around 4:30AM Monday morning in Domaine des Pins near Sainte-Justine-de-Newton in the Monteregie, close to the Ontario border. Five departments are currently fighting that blaze, but it remains out of control. 

There is some good news on the horizon, with a strong cold front arriving Tuesday afternoon, along with at least 10 to 15mm of much needed rainfall. The showers will taper off overnight into Wednesday morning, followed by gusty northwest winds and a sharp drop in temperatures. Highs will drop from the upper 20s Tuesday to the lower teens for Wednesday and Thursday. Overnight lows will approach the freezing point for many locations by Thursday morning, with the risk of frost.

The balance of the week will feature seasonable highs near 16C (61F), with sunny skies and dry conditions returning.

Wednesday, October 01, 2025

Frost and fire risk - outdoor burning prohibited across southern Quebec

Extremely dry weather has resulted in extreme wildfire conditions across southern Quebec. As a result SOPFEU has placed an outdoor burn ban in effect for parts of our region. This includes campfires and backyard burning. Rain fell in Montreal on only 7 days in September totalling 33mm, only 36 percent of the normal value. (Valley Weather) 

Frost Advisory in effect for southern Quebec for Thursday morning.

After only 33mm of rain in September and no precipitation in the forecast through next week, an outdoor burn ban has been put in place for large parts of southern and western Quebec, including and the MRC of Vaudreuil/Soulanges. According to SOPFEU, a wide area of southwestern Quebec in under extreme wildfire conditions. Even if you are not under the burn ban, you should refrain from any outdoor fires, this includes metro Montreal.

This means no campfires, or burning of any vegetation, and no fireworks. SOPFEU recommends that you check with your local municipality for specifics on the ban, but emphasize that no outdoor burning should take place. Drought conditions continue to intensify across the entire region, extending into eastern Ontario and northern New England. Burning restrictions are in place for many of those locations as well.

Most of southern and western Quebec is under extreme fire conditions (red) according to SOPFEU. This includes most of metro Montreal. Outdoor fires, including campfires are prohibited in most regions and not advised in metro Montreal. 

Strong high pressure will result in an extended period of low relative humidity, gusty north winds and warm temperatures. The result is very tinder dry vegetation, with the risk of any fire that may occur spreading quickly. No relief is in sight for the dry weather, we need rain desperately.

As the high pressure crests over our region Wednesday night, widespread frost is possible, with low temperatures dropping close to the freezing point for many. The low in metro Montreal will be around 3C (38F). Breezy and cool conditions will be in place Thursday as well, followed by a significant warning trend into the weekend. Daytime highs will approach near record values in Montreal, with highs near 27C (81F) by Sunday and Monday. The record Sunday for Montreal is 28.5C (84F) set in 2023. The normal high for early October is closer to 16C (61F).

The next chance for any precipitation will not come before next Wednesday at the earliest, with a cold front moving into southern Quebec.

Monday, September 29, 2025

Spectacular fall weather for Montreal - no rain in sight

A rocky beach along the shoreline of Lac St. Louis in Lachine. Water levels across the region remain at near-record low levels. The area will be getting an increase in water on October 18, with a planned increase in flow from the Moses-Saunders Power Dam in Cornwall, Ontario. The dam is operated by International Joint Commission and the Saint Lawrence Seaway. The flow will be increased over a 36 hour period, raising Lac St. Louis by as much as 15cm (6 inches).  (Valley Weather Photo)

September weather does not get any better than this in southern Quebec. However is does come at a cost, as drought conditions continue to worsen across the region. Starting with the upcoming forecast, we can expect nothing but sunshine through next Sunday. A dry cold front on Tuesday will result in gusty winds, up to 40km/h and a drop in temperatures, but no precipitation. 

The weekend was warm and dry in Montreal, with a well-above normal high of 24.9C (77F) on Sunday. Monday will be warm as well, reaching the middle 20s for highs. Overnight lows will be seasonably cool, around 10C (50F). The balance of the week will be slightly cooler, around 19C (66F) for highs and morning lows in the single digits. There will be a risk of frost on Wednesday and Thursday mornings.

By late week, strong high pressure will shift to our southeast, deflecting any storms away from out region. Temperatures will be on the rise again, with near-record warmth expected for the first weekend in October. There is no rain in sight. Montreal remains at 33mm for September, well below normal, and just above the record of 27mm set in 1961.

Saint Lawrence River International Joint Commission to raise water levels for Lac St Louis

The International Joint Commission will be increasing the flow from the Moses-Saunders Power Dam near Cornwall, Ontario on October 18. This is in response to the near-record low water levels on Lac St. Louis in the Montréal region. The last time this was required was back in the fall of 2012. Water levels are dangerously low in our region, with some areas to low for watercraft navigation. 

Water levels currently sit at around 67.88 feet on Lac St. Louis. The increase in flow on October 18, will bring the level of the lake up to approximately 68.24 feet. The increase in flow will only be for a 36 hour-period to help facilitate the seasonal removal of watercraft in our region. Many parts of southwestern Quebec and eastern Ontario remain in moderate to severe drought conditions.

Friday, September 26, 2025

Another extended period of dry weather for southern Quebec

A rare sight this September, as clouds and showers occurred in Montréal on two days this past week. Unfortunately amounts were light, with less than 10mm of rain falling at most locations. This is not nearly enough to bust the drought conditions prevailing across a wide swath of our region. (Valley Weather Photo)

Despite the rainfall this week, conditions remain exceptionally dry across southern Quebec. On Thursday, low pressure travelled south of our region, keeping the heaviest rainfall and thunderstorms across New York and parts of Ontario.

At Trudeau Airport a meager 3.9mm of rain fell Thursday, barely enough to wet the soil. That brings this weeks total to 9mm, again not nearly enough to break the drought conditions. The monthly total sits at only 28.4mm, well-below the long-term average of 89.2mm for September.

The dry conditions have resulted in a n early apple season across the region. The fruit is ready to be picked and is showing signs of stress from lack of moisture. The apples are starting to fall from the trees. Water levels as mentioned in previous posts, remain dangerously low. Be vigilant if boating on the St. Lawrence or Ottawa Rivers and tributaries.

After a few isolated showers Friday, the balance of the month into early October looks warm and dry. Expect daytime highs in the 20s, with overnight lows in the teens. A dry cold front Tuesday will result in cooler temperatures and perhaps some frost by the middle portion of next week. As far as precipitation is concerned, no rain is forecast until perhaps the second week of October.

Canadian Hurricane Centre forecast track of Hurricane Humberto, which should remain off the coast in the open waters of the Atlantic, but will bear watching for any impacts to Atlantic Canada. Meanwhile a tropical system may develop between Humberto and the US east coast. If it forms it would be named Imelda, and may produce heavy rain and high surf for the US coast. (CHC)

Strong high pressure will set up over Quebec deflecting any storms well to our south. This includes any tropical systems. The Atlantic has become active again, with Hurricane Humberto located 750km northeast of the Leeward Islands early Friday morning. Humberto is forecast to become a major hurricane this weekend, while remaining over the open waters of the Atlantic Ocean. 

Of more immediate concern is an area of low pressure south of the Bahamas that is forecast to become a tropical system this weekend. This storm is forecast to strengthen and pose a threat to the US southeast coast from Georgia to North Carolina early next week. More details this weekend as the storm further develops.

Monday, September 22, 2025

Some rainfall this week - however drought conditions persist across southern Québec

The last summer sunrise for 2025 over Montreal early Monday morning. Fall officially arrives at 2:19 pm Monday afternoon, September 22. The week ahead will not feel fall-like at all, with above normal temperatures expected to persist into the start of October. (Valley Weather Photo)

A weakening frontal boundary to the west of Montreal, may produce a few showers Monday morning, with a better chance late in the day, and perhaps even a rumble or two of thunder. Any rain will be welcome. Drought conditions are deepening across eastern Canada and New England. In Montreal, Sunday was our 14th day in a row with no precipitation. The monthly total stands 21.4mm, most of that falling in a single thunderstorm on September 4th. The normal precipitation for September is 89.2mm at Trudeau Airport. 

The North American Drought Monitor is reporting moderate to severe drought conditions (D-1, D-2) across large portions of southern and eastern Ontario and southern Quebec. Drought conditions then spread south and east across New England and southern Quebec. As a result, water levels remain dangerously low is several parts of the Great Lakes, Ottawa and St. Lawrence River watersheds including adjacent rivers and streams.

Vaudreuil Bay on Sunday afternoon, looking northeast towards the Island of Montreal. Water levels remain extremely low on both the Ottawa and St. Lawrence Rivers, with many docks sitting high and dry and rocky beaches where water should be.

The outlook for the week is a little more promising, but we are not seeing any drought busting rainfall. Several weak systems will produce scattered rain showers, resulting in perhaps 20mm or so by the end of the week, Any moisture is welcome.

The Autumnal Equinox occurs on Monday afternoon at 2:19PM. Despite a couple of cool mornings this past weekend, with even a hint of frost in many regions outside Montreal, warmer weather will prevail this week. Overnight lows dropped into the low single digits Sunday morning in the Montreal region, with even a few spots in the Eastern Townships below freezing. Sherbrooke reported a low of -3C (27F) Saturday morning and -2C (29F) on Sunday morning. Many locations reported frost and even a hard freeze ending the growing season for some.

High temperatures rebounded quickly into the low to middle 20s Sunday afternoon, with light winds and bright sunshine, a perfect final day of summer. This week will continue the trend of above normal temperatures, with highs in the low to even middle 20s and lows in the middle teens.

Thursday, September 18, 2025

Very dry weather conditions continue across southern Quebec - frost possible

The trees are starting to show signs of colour as we enter the last weekend of astronomical summer. The Autumnal Equinox occurs on Monday, September 22 at 2:19PM.

The first frost of the season is possible this weekend across portions of our region, especially away from metro areas and bodies of water.

Rain has been at a premium this September, with warm and dry conditions prevailing across most of Ontario and Quebec, eastward into Atlantic Canada, as well as adjacent portions New England. According to the Canadian Drought Monitor, nearly 71 percent of Canada is abnormally dry this September, with some of the worst conditions across eastern Canada. Atlantic Canada has reported one of the driest summers on record, with widespread drought, crop failures, wildfires and water shortages.

Here in Montreal, water levels are very low on all area waterways with many municipalities encouraging water conservation. Boating could be a dangerous endeavor, with rocks and debris appear in many spots as water levels continue to drop. One example of low water levels is Lac St-Louis at Pointe Claire, where the current level is at 20.68 metres (67.8 feet), close to the record low of 20.64 metres (67.7 feet) for the date. The average level is around 21.2 metres (69.5 feet) for September.

In June, only 22mm of rain fell at Trudeau Airport, that was followed by 133mm in July, however most of that fell in a single thunderstorm. August saw a return to dry and hot conditions, with only 67.1mm reported, again most of that falling on one or two days. September has been the driest month yet this summer, with only 19.4mm to date. The bulk of that fell in just a few hours on September 4. We have had only a trace of rain since then.

We need rain! This map above prepared by Agriculture Canada shows a significant departure from normal rainfall across most of the country, as much as 200 percent below normal in eastern Canada. This trend has been persistent all summer.

The forecast is not encouraging either as we head into the upcoming weekend. Strong high pressure has dominated our weather this week in southern Quebec. Temperatures have been above normal, with no precipitation. A weak cold front Thursday afternoon may produce a widely isolated shower or thunderstorm, but the chance is low and they will be scattered. The cold front will introduce a wind shift along with cooler temperatures for Friday. The high Thursday will be a summery 27C (81F), dropping to around 10C (50F) overnight and into the upper teens for Friday into the weekend. Some locations outside of metro Montreal do have a risk of frost Saturday night.

An upper level low and a frontal boundary will try to increase the coverage of showers early next week, but at this time amounts look too low to make a dent in the drought.

For the time being, conserve water, be vigilant if boating on area waterways, and be extremely careful with any outdoor burning.

Monday, September 08, 2025

Another stretch of dry weather ahead for southern Quebec

The Suburban, along with Tanguay, held our second annual Family and Pet Day in Cote St-Luc on Sunday. This was a rain date from August 24, when the threat for thunderstorms made it unsafe. Thankfully for the many in attendance, the rain held off this time, with the exception of a few menacing black clouds and gusty winds, along with an isolated sprinkle or two. (Valley Weather)

Strong high pressure has settled into southern Quebec on Monday morning, and will slowly drift southeast over the course of the upcoming week. This will result in another stretch of sunny and dry weather for our region. Temperatures have started off cool Monday morning, with many locations in the single digits, including 9C (48F) at Trudeau Airport. 

Montreal will warm to near 20C (68F) Monday and well into the middle 20's for the balance of the work week, with nothing but sunshine expected. The overnight period will feature clear skies, and cool temperatures, either side of 10C (50F).

The lack of precipitation this summer has resulted in drought conditions across many parts of southern Quebec, especially in the eastern portion of the province as well as Ontario and Atlantic Canada. (ECCC)

The next chance for rain will not come before the upcoming weekend. While the pleasant late summer weather is welcome by many, the area remains excessively dry. Large portions of Canada are actually in one stage or another of drought. In August, most of Quebec had below normal precipitation, with the deficit ranging from 25 to as much as 100 percent below the long-term average. The rain that has fallen in Montreal has often been too much at once, with too many days in between events.

We did manage a few millimetres of rain over the weekend, bringing Montreal up to 21.4mm for the month, but that amount remains below the long-term average to date for September. Southern Quebec needs a slow, soaking rain. Nothing is on the horizon at this point.

Friday, September 05, 2025

Strong winds cut power to over 70,000 homes across southern Quebec

Hydro-Quebec crews are on the ground Friday morning, repairing damage caused by a gusty cold front that moved across southern Quebec late Thursday. At the height of the outages, more than 70,000 customers were in the dark. That number is down to just under 40,000 Friday morning. (Hydro-Quebec)

A fast moving cold front generated strong winds late Thursday afternoon, cutting power to over 70,000 Hydro-Quebec customers across the southern part of the province. This included close to 4400 in the Montreal region. Hardest hit were the Laurentians and Monteregie regions. Early Friday morning, just under 40,000 customers remained without power. A majority of the outages were caused by downed tree branches coming in contact with wires and transformers.

The strong late-summer cold front dropped temperatures from a daytime high of 29C (85F) in Montreal, down into the upper teens in a matter of minutes around 5pm. A few heavier showers and embedded thunderstorms produced a gust front, with winds briefly in the 60-100km/h range locally. Officially at Trudeau Airport, the wind gusted to 63km/h. There were no weather warnings in effect at the time of for the front. Some much need rain fell as well, with 17.8mm recorded at Trudeau Airport, while I measured 11mm at my home on Ile Perrot.

We can expect a calm, sunny Friday, with a warm high near 24C (76F). Winds will increase during the afternoon hours once again, gusting between 20-50km/h. On Saturday, an upper level low will drift over the region, with a cool, breezy and showery day expected, the high will only be 17C (63F). Sunday at this time looks fair, with some cloudy periods and perhaps an isolated afternoon sprinkle or two. The high will be 20C (68F).

Thursday, September 04, 2025

Welcome to Meteorological Fall

September skies can be spectacular as Summer begins to give way to Fall. This vivid rainbow developed late Tuesday afternoon after some isolated showers and thunderstorms moved across Ile Perrot and the West Island of Montreal. (Photo: Valley Weather)

Well fall arrived September 1st, at least according to the meteorological community, astronomical autumn will catch up on the 22. September has started off warm, with well-above normal temperatures since Labour Day Monday. Clouds are on the increase as I write, with a strong cold front to our west. While Montreal is at 23C (73F) as of 10:30AM, Toronto, behind the fall-like front, is down to 12C (54F).

The front will produce some gusty southwest winds today, up to 50km/h, along with some thunderstorm activity later this afternoon. A period of steady rain Thursday evening, will taper off by morning, with a fair and warm day forecast Friday.

The cooler air will eventually arrive in Montreal, but it may take a day or so. Another slow moving cold front and upper level low will bring us showers and thunderstorms Saturday. On Saturday, the core of the colder air will arrive, along with showers and a high of only 17C (63F). Sunday into early next week will feature cool nights, with seasonable days along with fair weather through Wednesday.

Our hot and dry summer is now in the record books. In June, only 22mm of rain fell at Trudeau Airport. That was followed by 133.1mm in July, but most of that fell in a few hours on the 13th. August was the hottest month this summer, with 7 days over 30C (86F), including a 6 day heatwave, and the warmest temperature this summer for Montreal,  35.1C (95F). The heatwave included 3 record highs. Montreal managed 70mm of rain, but most of that fell during the last few days of the month. In fact, only 7 days has measurable rainfall at Trudeau Airport.

September heralds the change of seasons. The skies can be dynamic as one season yields to the next. Indications are we can expect temperatures and precipitation fairly close to normal. We will lose nearly 90 minutes of daylight in Montreal from the start to the end of the month. The trees are already showing signs of colour. The fall foliage may be greatly diminished this fall, as many trees are showing signs of heat stress, which can limit the colours.

Thursday, August 28, 2025

Slow moving cold front bringing much needed rain to Montreal

A slow moving cold front has been lying just to the northwest of Montreal all day Thursday. That front will finally press southeast this evening, bringing with it a decent 15-25mm of rain for the Montreal region. Friday will be breezy, cloudy and cool, feeling very much like Autumn across southern Québec.

It has been a dry month and a dry summer. To date, Montreal has measured 41.2mm at Trudeau Airport this August, most of that falling on just a couple of days. This is well below the long-tern average for the month of 93.6mm. The lack of rainfall has been evident, with watering restrictions, dangerously low levels on area lakes and rivers and heat stress reported to crops, tress and even your lawn.

Thursday afternoon we are watching a very moist and achingly slow moving cold front draped from southwest to northeast, located just north of Montreal. This front is the dividing lone between a fall-like airmass and warmer more humid air to the south. As I write, Montreal is 24C (76F), while Ottawa is only 17C (63F). Along the front steady rain is falling, with a few rumbles of thunder.

That front will begin to affect the Montreal region late this afternoon and especially this evening and overnight. Steady rain will persist into the morning hours on Friday along with cooler temperatures. Rainfall amounts will settle into the 15-25mm range. Not a drought-buster, but certainly helpful.

Overnight lows will drop into the teens, and as winds back to the northwest, temperatures will struggle to rise on Friday under cloudy skies reaching near 17C (63F).  Saturday will be cloudy and cool as well, feeling more like September. But the news is not all bad for the long holiday weekend, with sunshine expected both Sunday and Monday, with daytime highs rebounding into the middle 20's. Nearly perfect late summer weather for the Labour Day holiday.

Thursday, August 21, 2025

Hurricane Erin pounds the Eastern Seaboard with high surf

Pounding surf from Hurricane Erin inundates homes in Buxton, North Carolina along the coast of Hatteras Island on the Outer Banks. Despite being over 300 kilometres form the coast, Erin has produced significant flooding and some structural damage. (WTKR)

Category 2 Hurricane Erin was located 340km east of Cape Hatteras early Thursday morning, with 165km/h (105mph) winds and a central pressure of 945mb. The large and powerful storm sent towering waves crashing into coastlines from the Carolinas to Nova Scotia, producing coastal flooding and dangerous rip currents. Mandatory evacuations were in place for Hatteras and Ocracoke Islands on the Outer Banks of North Carolina, where State Highway 12 was closed due to ocean over wash and significant flooding over several high tide cycles. Some structures have already been damaged. 

Erin is a large storm, stretching over 1200 kilometres in  diameter, with hurricane force winds extending outward165km from the centre, and tropical storm force winds an incredible 520km from the eye.

On Thursday morning, Erin was located 340 kilometres to the east of Cape Hatteras. The storm was forecast to race off to the northeast today passing south of Atlantic Canada on Friday. Heavy surf is forecast from the Carolina's to Newfoundland for the next 36-48 hours. (Windy.com)

For those of you who frequently read my blog, you are aware of my passion for the Outer Banks. I had been vacationing their since 1991. During my last trip in 2018, I sat under Jennette's Pier in Nags Head, with my dog Bella. It was her last trip. Our time their was spectacular. Today, the Pier is reporting a wind gust to 87km/h, with a 2 to 4 foot surge and towering waves. Not an ideal beach day to say the least.

Erin will continue to produce coastal flooding along the Outer Banks, spreading north into Virginia and the Middle Atlantic States. Later today, gusty winds and heavy surf will move into the Northeast and New England including Long Island and Cape Cod. 

Earlier this week, Hurricane Erin produced heavy rain and flooding in Puerto Rico. At the time, Erin was a powerful category 5 storm, with winds in excess of 160mph. (Unknown Facts)

The heavy wave action will begin to impact the south facing coast of Nova Scotia and Newfoundland Friday and into the upcoming weekend before Erin races off to the northeast. Winds may gust to 70km/h along the Nova Scotia coast late Friday and Saturday. Gale to storm force winds are expected in the offshore marine waters of Newfoundland, with seas building to 8 to 10 metres (26-33 feet) by Saturday.

The tropical Atlantic will continue to remain active, with the National Hurricane Centre watching two more areas for development as we head into the peak part of the season.

Sunday, August 17, 2025

A taste of autumn for Montreal

A NOAA satellite image showing powerful hurricane Erin Sunday afternoon, located northwest of Puerto Rico. The storm should stay away from land, but will grow in size, sending towering waves towards the Eastern Seaboard and Atlantic Canada coastline this week. (NOAA/NHC)

And just like that, mid-summer weather became September-like in less than 6 hours. If you needed a break from the intense heat, you will have one this week. Montreal did manage another 30C (86F) day on Saturday, before a strong cold front swept across the region early Sunday morning. The front was accompanied by gusty northeast and eventually northwest winds, some much needed rainfall and rapidly falling temperatures. By mid-morning, the mercury had fallen to 15C (59F) here on Ile Perrot.

A decent 11.6mm of rain fell along the front at my weather station on Ile Perrot, but we need more to alleviate the dry summer we have had. Watering restrictions remain in place for several communities on the West Island as well as Vaudreuil-Dorion and here on Ile Perrot. 

The fall-like airmass that moved into southern Quebec will be with us for most of the upcoming week, a big change from the hot and humid weather that has persisted for most of the summer. Late afternoon sunshine did allow the temperature to rebound Sunday, close to 21C (70F) as I write this update. We can expect clear skies overnight, with cool lows in the upper single digits to around 12C (54F) in downtown Montreal. Monday will be fair and cooler, with a high of 21C. Clouds increase Tuesday as another frontal system approaches southern Quebec. 

The Canadian Hurricane Centre forecast track of Erin as the storm turns north this week and approaches Canadian offshore waters. (CHC/Environment Canada)

Hurricane Erin

Erin became the first Atlantic hurricane of the 2025 season on Saturday, strengthening into a major Category 5 storm, with 255km/h winds, less than 24 hours after forming. Thankfully, the catastrophic strengthening occurred far from land. 

Erin has since weakened slightly to a Category 3 storm, with winds of 205km/h as of 5pm Sunday afternoon. Erin was moving west northwest at 20km/h, with a forecast turn to the northwest and eventually north expected. The center of the storm was located 445km northwest of San Juan, Puerto Rico, with a barometric pressure of 946mb.

To date Erin has avoided any direct impacts to land, but her size and strength has spread heavy rains in Puerto Rico. Erin is expected to continue to grow in size and may deepen once again as the storm moves offshore of the United States east coast and eventually moving southeast of Atlantic Canada my the end of the week. Heavy surf and rip currents are forecast to spread from Florida to Newfoundland this week.

At this time, a tropical storm warning is in effect for the Turks and Caicos Islands as well as the southeastern Bahamas, with Erin producing strong winds and heavy rain as it brushes this region Monday. All interests from the Carolinas to Atlantic Canada should monitor the progress of hurricane Erin this week.

Hurricane Erin will have no impact on the weather here in southern Quebec.

Thursday, August 14, 2025

Slightly cooler - less humid weather for Montreal

The sudden heavy rain on Wednesday ended a month long dry spell in most locations across the Montreal region. The rain resulted in a white, foamy substance forming that but made roads extremely slippery at the onset. That combined with low visibility resulted in several accidents. The foam was a result of a lack of rain producing a significant buildup of oils and other contaminates on road surfaces.

The historic heatwave is over for Montreal, after six 30C (86F) plus days in a row, the high Wednesday reached only 29C (85F). More importantly, rain fell on the region. Strong thunderstorms swept across the Island of Montreal, producing heavy rain, strong winds and plenty of vivid lightning during the morning hours Wednesday. It had been bone dry for nearly a month in Montreal, but 19.4mm fell at Trudeau Airport during the morning storms, with amounts across our region ranging form 7mm to 20mm. Certainly not a drought buster, but more than welcome.

The rain has improved the wildfire risk in southwestern Quebec, but conditions remain poor southeast of Montreal across the Townships and Beauce regions. You can add Hudson to the growing list of communities that have watering bans in effect. Water levels remain low on all area waterways, so conservation is key at the moment whether or not your community has restrictions.

As far as temperatures are concerned, the weather will remain warm, with highs between 28C and 32C (85 to 90F) through Saturday. On Sunday, a much stronger cold front arrives, with showers and thunderstorms followed by a significant pattern change that will allow much cooler air to settle into southern Quebec next week. More on that in later posts. 

We also need to watch closely Tropical Storm Erin, which is forecast to develop into a major hurricane by late in the weekend. Erin is still far away, located 1595 km east of the Leeward Island on Thursday morning, with 85km/h winds. The storm is no threat to land at the moment.

The most recent heatwave established a ton of record highs across eastern Canada. Some locations, such as Newfoundland and Prince Edward Island recorded their hottest days ever. In Quebec, Gaspe Airport reached 36.2C (97.2F) on Tuesday, the warmest day ever recorded at that location dating back to 1915. It surpassed the previous high of 36C (97F) set back in 2003.

In Montréal, our string of 30C days this summer has now reached 17, well-above the seasonal average of 9. Many of those have been above 32C (90F) and two above 35C (95F). Overnight lows were warm as well, breaking several records this summer.

Wednesday, August 13, 2025

Historic heatwave coming to an end in Montreal - thunderstorms likely

Another hot sunset in Montreal. The excessively hot and dry summer has taken a toll on trees and vegetation in the region. Many are showing signs of significant heat stress and lack of moisture. The hot weather has been historic in many parts of eastern Canada, with dozens of new temperature records established from Ontario to Newfoundland. Relief is on the way for southern Quebec Wednesday.

Severe Thunderstorm Watch issued for Montreal

The historic heatwave that has gripped the eastern part of Canada for nearly a week now will come to an end in Montreal Wednesday. A cold front is moving across Ontario as I write, with showers and thunderstorms developing in advance. Some of the storms may be on the strong side, with gusty winds and heavy rain the main threat. We need the rain, let's just hope it does not come all at once.

Tuesday was another sweltering day, with a record-breaking high of 34.6C (94.3F) at Trudeau Airport. It was the third consecutive day with record heat following Sunday's 34.4C (94F) and Monday's 35.1C (95F). Overnight lows have remained in the low to middle 20s. Montreal was still 29C (85F) at midnight early Wednesday.

Patly sunny skies Wednesday morning will give way to clouds, showers and thunderstorms through the noon hour and into the evening. Temperatures will be warm again today, reaching 30C (86F) before the rain. It will be a muggy day. The air behind the front will be cooler and less humid, with highs in the middle 20s expected Thursday and Friday.

The heatwave has resulted in watering bans being issued for several communities across southern Quebec. The wildfire risk has been high as well, with numerous significant fires being reported in Ontario and across Atlantic Canada and Newfoundland.

Dozens of new record highs were established over the last few days. Badger, Newfoundland reached 36.7C (98F) on Tuesday, a tie for the warmest temperature on record for the province. Miramichi, New Brunswick reached 38.6C (101.5F).

Montreal is also moving up the list for the warmest summer on record. As of Tuesday, we had recorded 10 days of 32C (90F) or higher. That places us fifth in the record books behind the 14 days recorded back in 2020. 

The heatwave has sadly resulted in at least one heat-related death in Montreal, and there have likely been others. The prolonged effect of days of high heat is taking a toll on many. The cooler weather and rain will be more than welcome.

Monday, August 11, 2025

Record warmth for southern Quebec through Tuesday

The weather was hot for the Annual Firefighters Day Parade in Pincourt on Saturday, August 9. Spectators lined the streets of the municipality as First Responders and emergency vehicles slowly passed by. The event has been hosted by the Pincourt/Notre-Dame-de-L'Ile-Perrot Firefighters since 1980. Departments and Agencies participated from the Island of Montreal, across the Monteregie and even eastern Ontario. (Valley Weather Photo)

Heat Warning remains in effect for southern Quebec and eastern Ontario.

The warmest air of the summer has settled over the region. Strong high pressure anchored off the eastern seaboard will continue to pump hot and increasingly humid air into southern Quebec to start the work week. The result will be a long period of very warm temperatures along with elevated humidity. With highs in the 30s and humidity readings near 50 percent, humidex values will easily climb through the 30s to near 40C (104F) each afternoon. Overnight lows will remain very warm in the low to middle 20s.

This type of heat is extremely dangerous, especially for the very young, seniors and pets. Stay hydrated, and limit outdoor activities to the early morning hours or near sunset. Find relief in air conditioned buildings such as malls or theaters. Montreal has plenty of shady spots by the lake or river, which offers some slightly cooler air.

Monday will make this an official heatwave in Montreal as the temperature will soar above 30C(86F) for the third consecutive day. On Saturday, Montreal reached 32.3C (90F), while Sunday we warmed even more, with a record high of 34.4C (94F). That surpassed the long-standing 1914 record for the date of 32.8C (91F). Montreal should be even warmer on Monday and Tuesday. The forecast high today is 34C (94F), the record for the date is 35C (95F), set back in 1944. On Tuesday, Montreal is expecting a high of 35C (95F), which should easily break the 2002 record of 32.7C (91F). 

Another concern of the recent heatwaves has been the lack of rainfall. Gardens, crops and trees are starting to show signs of drought and heat stress. Since July 19, Trudeau Airport has recorded only 2.8mm of rain. No rain has fallen in August to date. Vegetation is tinder dry and any outdoor fires are not recommended and in some cases banned all together. Check with your municipality or better yet just don't do it. Most wildfires in Quebec are a result of human activities, such as the burning of trash, discarded cigarettes or campfires.

According to SOPFEU, the fire danger Monday and Tuesday ranges from very high to extreme across the southern and western portion of the province. The same is true across parts of Ontario east to Atlantic Canada. Several significant brush fires have been reported in those regions. Remain vigilant.

Some relief arrives Wednesday in the form of a weak cold front. A few showers are possible. 

Thursday, August 07, 2025

Extended period of hot and dry weather for southern Quebec

Less than 1mm of rain has fallen in Montreal during the last three weeks. Lawns are turning yellow and leaves are falling as moisture starved vegetation reacts to the extremely dry conditions. Hot and dry weather is forecast through Tuesday for the St. Lawrence Valley. (ValleyWX Photo)

UPDATE: Saturday, August 9, 6:30PM: Heat Warning issued for metro Montreal.

This has certainly been a hot and dry summer, briefly interrupted by two flooding rain events. If you take a look at Montreal since the start of meteorological summer on June 1st, 155mm of rain has fallen. Not bad right? Break it down and it explains why lawns are turning yellow and leaves are falling from moisture starved trees. In June, only 22mm of rain fell. July was better, with 133.1mm, however, most of that fell on two days, including the flash flooding event of July 13. The lack of frequent precipitation has often been accompanied by searing heat.

August has had no precipitation to date at Trudeau Airport. In fact, only 0.6mm of rain has fallen in the last 20 days. That trend is forecast to continue, with only widely scattered, mostly elevation dependent showers through Tuesday. Here in the St. Lawrence Valley, we are expecting hot and dry weather, with temperatures and eventually humidity levels on the rise.

A grass fire, started by a combine, burns in Leeds and Grenville County in eastern Ontario this week. The dry weather extends from the Prairies into Atlantic Canada. In many parts of Ontario, water and outdoor burn bans are currently in effect as the fire danger remains elevated. (OPP East Photo)

Thursday will be sunny as high pressure builds across the region and extends to our southeast. As that high pressure moved to our east, temperatures will begin to rise. Highs will range from 29C (85F) Thursday, into the low and even some middle 30s by Monday. Overnight lows will be on the rise as well, from the middle teens Friday into the low to even middle 20s in urban areas by Sunday night.

The next chance for any rain or thunderstorms will not come before late Tuesday as a cold front moves southeast from Ontario.

The dry weather has prompted outdoor burn bans for a large part of southern and eastern Ontario. So far in Quebec, the only region with very high to extreme fire risk is the Gaspe region. That may change. Best advice is to avoid burning anything outdoors as most vegetation is significantly lacking in moisture. 

The dry weather extends across a broad region of Canada, with fires burning from Alberta to Newfoundland. So far Quebec remains fortunate, with only 5 active fires according to SOPFEU. This has allowed the province to send firefighters and equipment to Alberta, Saskatchewan, Manitoba and Newfoundland.

For now the air quality has improved in southern Quebec, but with the amount of fires currently burning across the country, it is only a matter of time before the smokey skies return.

Saturday, August 02, 2025

Poor air quality forecast for southern Quebec Sunday

Widespread smoke and poor visibility is set to return to southern Quebec into Sunday. Numerous wildfires are burning out of control across northern Saskatchewan and Manitoba. The smoke has resulted in air quality alerts being issued across Ontario and Quebec as well as the Great Lakes, Upper Midwest, New England and the northeastern US.

Air Quality Alert for the entire region.

Gusty westerly winds are expected to carry wildfire smoke from western Canada into the lower levels of the atmosphere in Montreal and Ottawa this evening and especially Sunday. An AQI reading greater than 100 will result in very unhealthy air for any outdoor activities. The smoke will be widespread across southern and eastern Ontario, southern Quebec as well as New York and New England. Poor air quality from fine particulate matter related to fire smoke, can result in burning eyes and nose as well as difficulty breathing.

Strong high pressure is expected to slowly drift across southern Quebec over the next few days, providing our region with dry weather well into the upcoming week. Gusty west winds and low relative humidity levels will increase the fire risk across the region. The Montreal region has had less than 1mm of rain over the last 16 days. The dry weather has been accompanied by very warm temperatures at times, with 9 days over 30C (86F) recorded at Trudeau Airport during the month of July.

Montreal also managed 138mm of rain, well over the normal amount of 91mm. Most of that fell during the flash flooding of July 13, when a new July monthly record of 81.6mm fell at the airport. That included 22.4mm in just 15 minutes. The intense rainstorm erased the July 10, 2024 record of 79.2mm.

So for the upcoming week, we are looking at smoke clearing by Monday, with sunshine and clear nights. High temperatures will be in the upper 20s to near 30C, with overnight lows in the middle teens. No rain is expected through next Friday.

Wednesday, July 23, 2025

Heat warning for Montreal - followed by fall-like stretch of weather to begin August

A towering thunderstorm over Pincourt last Thursday, July 13. The storm produced torrential rain, but thankfully was quick moving, alleviating the flood risk. More strong storms are possible this Thursday and again next Tuesday, before much cooler weather arrives to start the month of August in Montreal. (Valley Weather Photo)

Environment Canada has issued a heat warning for southern Quebec for Thursday, with high temperatures expected well into the 30s, and humidex readings approaching 40C (104F) in Montreal during the afternoon hours.

The hot weather is part of an expanding heat dome that has resulted in widespread weather warnings across a large portion of the central and eastern United States and into southern Canada. Along the circumference of that heat dome, heavy thunderstorms have been occurring through the Dakotas, upper Midwest and Great Lakes into parts of Ontario.

For Montreal, we can expect a very warm and humid Thursday, with a forecast high of 33C (91F). Clouds will increase late in the day as a cold front advances into the St. Lawrence Valley from central Ontario. Showers and thunderstorms are likely, persisting into Friday. Some may be on the stronger side, with heavy rain and gusty winds possible.

Friday will be a little cooler, with daytime highs in the middle 20s. The heat will build again Saturday though Monday, with highs once again near 30C (86F). Overnight lows will be in the upper teens to near 20C.

By Tuesday, a more potent cold front will result in another round of showers and thunderstorms. Finally high pressure moves into southern Quebec to end the month and start August, with much cooler weather expected. Highs will drop into the lower to middle 20s for many locations, with overnight lows in the lower teens and even some single digits. The early taste of Autumn for Montreal will prevail during the first week or so of August. 

Monday, July 21, 2025

Stretch of near-perfect summer weather for Montreal

Skies cleared on Sunday afternoon, providing ideal weather for the annual car show at Pointe-du-Moulin in Notre-Dame-de-L'Ile-Perrot. Unfortunately the threat of morning rain resulted in lower numbers of cars on display and patrons attending.
(Valley Weather) 

Monday will be as perfect a summer day as you can expect in Montreal in July. High pressure building in behind Sunday's cold front, will result in nothing but sunshine, low humidity, cooler temperatures and smoke-free skies. Highs will be in the low to middle 20s, cooling back into the lower teens by Tuesday morning, with even a few single digits possible outside the city. Winds should remain light.

This ideal summer weather will persist through Wednesday, before heat and humidity being to build again. Active weather returns by Thursday as higher humidity levels and warming temperatures nearing 30C (86F), will result in numerous showers and thunderstorms. The muggy weather will continue into Friday.

Morning showers drift to the south as skies clear Sunday afternoon on Ile Perrot. A lone ship travels Montreal bound through the St. Lawrence Seaway on Lac St Louis. (Valley Weather Photo)

Over this past weekend, we had a few showers late Saturday into Sunday, but the front proved to be rather unimpressive for southern Quebec, a welcome relief after the flash flooding and thunderstorms of the past week. For the short-term, the hot and humid air has settled back south into the central and southern US, where millions are under heat advisories. Strong high pressure in those regions has resulted in a heat dome dominating the weather. Temperatures will soar into the middle and upper 30s, with humidex (real feel) readings over 38C (100F).

Along the periphery of the heat dome, slow-moving strong thunderstorms will continue to produce heavy rain and thunderstorms, in what is quickly becoming the summer of the flash flood across North America.

For now, that weather will remain to the south of Montreal and the St. Lawrence Valley. By next weekend, we are looking at pleasant weather once again, with perhaps the hot and humid weather pushing back north for the final days of July.

Friday, July 18, 2025

Much needed break from the heat and humidity for Montreal

Thursday's strong thunderstorms approach the Island of Montreal off Lake of Two Mountains during the late afternoon. (Valley Weather Photo)

A fresh and cool air mass has descended upon Montreal Friday morning, a welcome relief from the oppressive heat and humidity of the past week. We had one more steamy day on Thursday, with a high of 30.6C (87F) in Montreal. It was the third 30C plus day in a row and 7th this month. Many of those days have had elevated dew points and humidex readings near 40C. So far this summer, Montreal has recorded 12 days warmer than 30C (86F), with 6 days just under at 29C (85F).

A strong cold front swept across the southern portion of the province, producing waves of heavy thunderstorms. Thankfully the storms were fast moving, and that managed to limit the flood potential, at least in Montreal. Trudeau Airport measured 26mm, bringing the monthly total to a very wet 135.2mm. Strong winds accompanied the storms as well, with a gust to 74km/h at Trudeau and 89km/h at Saint-Hubert.

A flooded delivery car on a highway near Quebec City Thursday afternoon. An image all too familiar to Montrealers. Between 75 and 85mm of rain fell on the provincial capital in under two hours causing significant flash flooding. (TWN)

While we escaped the flooding this time, Quebec City did not. Both Levis and Sainte-Foy reported significant flash flooding after 75-85mm of rain fell in under two hours. Roads were inundated with many water rescues taking place. Many homes and businesses sustained significant flooding as well. 

The good news is that we are in for a cooler stretch of weather. After a refreshing morning low of 15C (59F) on Ile Perrot, we can expect daytime highs around 24C (76F). Saturday ooks perfect as well, with sunny skies, low humidity and a high of 25C (77F).

Low pressure will skirt along the international border for Sunday, with light rain forecast, perhaps around 10-15mm. Next week will start off cool and dry, before the heat builds again for the second half of the week.