Calmer, warmer weather week ahead for Montreal

Strong winds and isolated thunderstorms produced widespread power outages and damage over the weekend across southern Quebec. This tree fell onto several parked cars on Leclaire Street in the Hochelaga district of Montreal late Sunday afternoon. (Submitted photo to CTV News)

Happy Meteorological Summer!

The weekend was unsettled as predicted, with cool weather and scattered thunderstorms at times. An upper level low drifted southeast off the New England coast and is moving away from southern Quebec. The circulation around that storm may produce some afternoon clouds and perhaps a shower or rumble of thunder in Montreal, but that should thankfully be the end of this system as it drifts into Atlantic Canada.

High temperatures on Monday, will be warmer than over the weekend, reaching 21C (70F). Winds should ease after a very blustery weekend. The balance of the week looks sunny and dry, with increasing warmth through Friday. Highs will range through the middle and upper 20s, with lows in the middle to high teens.

Speaking of wind, at Trudeau Airport, peak gusts were observed at 78km/h Friday, 67km/h Saturday, and 68km/h on Sunday. Gusts reached as high as 90km/h in other locations. Those winds caused widespread power outages, especially Friday, when over 40,000 customers were in the dark. The same was true across eastern Ontario, where nearly 90,000 homes and businesses were in the dark. In Montreal rain fell heavy at times, with 20-30mm falling since Friday afternoon. 

The thunderstorms also produced a significant amount of lightning strikes in the Montreal region Friday afternoon, the most this year to date. A cooler spring has resulted in fewer thunderstorms so far in Montreal.

Strong low pressure that produced heavy thunderstorms across southern Quebec, delivered a late season snowstorm to Mount Washington, New Hampshire on Saturday. As much as 15cm fell at the summit. (Mount Washington Toll Road)

The storms on Sunday were isolated in nature, but packed a punch. One storm knocked down several trees, including one onto several parked cars in the Hochelaga district of Montreal. Meanwhile in LaSalle, an inflatable play structure was lifted into the air at an outdoor celebration at Oullette Park, causing 11 injuries, 6 serious enough to require hospitalization.

The low pressure produced heavy rain and gusty winds across all of eastern Canada and New England. There were widespread reports of very strong winds as well several boats were damaged along the New England coast. Inland heavy snow blanketed portions of the highest elevations, including Mount Washington in New Hampshire.

Strong wind gusts Friday also resulted in widespread power outages across eastern Ontario. Over 90,000 homes and businesses were left without power, stretching into the weekend for many. (Ontario Provincial Police Photo)

Rainy and windy start to the weekend for Montreal

Periods of heavy showers and gusty winds are possible late Friday into the overnight hours in southern Quebec. Winds may gust to 80km/h in the St. Lawrence Valley.

Special Weather Statement issued for Montreal for gusty northeast winds between 50-80km/h this evening.

An unsettled weather pattern is with us for the next several days as an omega block in the atmosphere dominates our weather. An omega block, named after the Greek letter, is basically an atmospheric traffic jam allowing for a stagnant weather pattern. In our case, strong high pressure lies over the central portion of the continent, while deep upper levels lows sit near both coasts.

Here in Montreal, we can expect a rather cool, wet period of weather, with frequent troughs of low pressure pinwheeling around the aforementioned upper low over central Quebec. As the upper level low slowly slides to our southeast, west winds will veer to the northeast and increase Friday afternoon, gusting up to 80km/h at times into the overnight hours.

Rainfall may be briefly heavy at times Friday, with a few embedded thunderstorms possible late this afternoon and into the overnight hours. Amounts may reach 15-25mm for Montreal. Temperatures will be on the cool side in the middle teens to perhaps 20C (59F to 68F) for those who see some sunny breaks. Morning lows will be near 11C (52F) overnight Friday and again Saturday.

Partly cloudy skies will prevail most of the weekend, but with plenty of instability in the air. Therefore the risk for cloudy periods and showers remains all weekend and even into Monday. Some of the highest elevations across southeastern Quebec and northern New England may even see a snowflake or two.

Warmer and drier weather will return by the middle of next week, as the block begins to breakdown and the weather systems begin to move freely again from west to east.

Warmer weather briefly returns to Montreal

Intervals of rainy weather and warm sunshine over the last two weeks has resulted in an explosion of growth and colour across southwestern Quebec. Unfortunately along with that has been a significant increase in pollen for suffering from seasonal allergies. (Valley Weather) 

Spring can certainly be a little fickle in Montreal, for lack of a better scientific term. Saturday was short and t-shirt weather, with a muggy high into the middle 20s. Sunday on the other hand was unseasonably cold and damp, with a biting northeast wind up to 50km/h. The high managed to reach 13C (55F) late in the day, along with up to 20mm of rainfall as of early Monday morning.

The good news on Sunday was that the rain ended just in time for the waving of the green flag at the Formula-1 Canadian Grand Prix. The race was won by F-1 Mercedes driver, 19-year old phenom, Kimi Antonelli. Just some light drizzle occurred during the race, but the cooler temperatures did make the track surface a little slick at times.

As we start the week, a warm front lies just to our southwest, with a chilly rain falling. That will change quickly as the front lifts north of Montreal later today, with a wind shift to the southwest. Winds may gust up to 60km/h into Tuesday afternoon. The front will set the stage for a warm and at times muggy weather through midweek, with highs in the middle to upper 20s through at least Wednesday.

A cold front arriving late Wednesday will produce isolated showers and perhaps a thunderstorm, before cooler weather arrives on Thursday. High temperatures will fall to around 20C (68F), with lows into Friday morning near 11C (52F)

Briefly looking ahead to next weekend, an upper level low may bring us another shot of unseasonably cool air, along with scattered showers on both Saturday and Sunday. High temperatures are expected to fall back into the middle teens, with breezy northeast winds returning. The poor weekend forecast is still a few days away, so lets hope for a significant change in this pattern that has resulted in such variable weather through April and May. 

Go Habs Go!

Rainy cool weather expected for the Canadian Grand Prix

Regardless of the date the event is held, the Canadian Grand Prix has often been impacted by challenging weather. A rainy, cool race day is forecast for this Sundays race. (Formula1.com)

Montreal has had a stretch of spectacular weather over the last week or so, but sadly that is about to end just in time for the F1 Canadian Grand Prix at Circuit Gilles Villeneuve on Sunday. Rain is forecast most of the day Sunday, along with breezy and cool conditions. Low pressure will lift across the central Great Lakes and allow for a southeast flow of cool and damp air off the Atlantic on race day.

The result will be 10-15mm of rainfall on Sunday, along with race temperatures between 10C and 13C (50-55F). The good news is that with a later start time than usual of 4pm, the rain may become more showery late in the day, with a chance that the bulk of the precipitation will have ended.

The very first F1 Canadian Grand Prix in Montreal was held on October 8, 1978 in rainy, cold weather, with even a hint of a few wet snowflakes in the air. The race was won by hometown hero Gilles Villenueve, his first career F1 win. The temperature at race time was only 6C (43F). (Formula1.com)

The last week has presented typical May weather for southern Quebec. We managed a 5 day stretch of sunny and warm weather, the highlight being Tuesday when we reached 28.3C (83F), the warmest day so far in 2026. A dry, breezy cold front swept across the region late in the day Wednesday, leaving us with a couple of sunny, but unseasonably chilly nights. The Friday morning low at my weather station Ile Perrot was only 3C (38F).

The good news for race fans is that we have two spectacular days on tap for all the events taking place around Montreal and on Ile Notre-Dame. Highs on Friday will be near 20C (68F), warming into the low 20s Saturday, along with increasing high clouds. Unfortunately the weather will not hold for Sunday.

Warmer weather along with clearing skies will return for Monday.

Soaking rain to start - much warmer weather on the horizon

Dark clouds advance across the Montreal region on Tuesday, as a stubborn, chilly and moist airmass remained in place over the last few days. There was even some overnight frost reported outside the metro locations. Warmer weather is on the way for the upcoming holiday weekend. (Valley Weather Photo)

Spring has certainly been off to a rather slow start across southern Quebec, with a frequent chill in the air. Even over the weekend when the sun was out, a chilly wind held temperatures down in the lower teens. We may see that change over the course of the next week.

After a couple of cold nights, cloud cover managed to keep overnight lows near 10C (50F) in Montreal. This will set the stage for a slow warming trend into next week.

To start however, we are dealing with several areas of low pressure, the main culprits off the New England coast and a secondary system over Michigan. A warm front will lift north of Montreal over the next 24 hours, accompanied by a soaking rain. There may even be a rumble or two of thunder. Amounts will range from 15-30mm over the region.

Thankfully the flood risk has lowered to the point that many municipalities are removing pumps and flood barriers. The level Wednesday morning in Sainte-Anne-de-Bellevue was at 23.11 metres, now below minor flood stage which is set at 23.30 metres. Some fluctuation in levels may occur over the next few days, but it appears the spring flood risk is now over for the Montreal region.

After two days of cloudy, wet weather, sunshine is set to return for the upcoming Victoria Day holiday weekend. Highs will climb to near 21C (70F) all weekend, with lows warming into the low teens. By Monday and Tuesday, our daytime highs may nudge to the warmest reading so far this year as we push 25C (77F), locally even warmer close to the Ontario and New York borders.

A battle of the seasons - flood risk lowering for Montreal

Despite water levels lowering on the Ottawa River this weekend, pumps will remain in place in Sainte-Anne-de-Bellevue and other municipalities until the threat is over. (Valley Weather)

The weather was anything but May-like on Saturday across southwestern Quebec, with a cold northwest wind, chilly temperatures and even some sleet and graupel falling from the sky. An upper air disturbance produced enough instability to generate a few lightning strikes early Saturday afternoon. Temperatures remained quite chilly throughout the weekend, with scattered frost reported. Highs were in the 9C to 12C range (49-54F), with low temperatures a few degrees either side of the freezing point.

Early Monday morning, we have milder air trying to work into the region, accompanied by some robust showers along a warm front. That front should clear the region by noon, allowing for a few breaks and gusty, warm southwest winds. Temperatures should warm into the upper teens and even a fews 20s around. The same can be expected for Tuesday, before a cold front sweeps across eastern Ontario and southern Quebec.

That front will produce a few showers and even a thunderstorm, before a soaking rain develops into Wednesday. Temperatures will fall back to the single digits for highs on Wednesday, as the seasons continue to battle across most of Canada.

The weather was cold enough for sleet to fall over the weekend in parts of southern Quebec. (Valley Weather)

Spring Flooding

The news is better concerning the ongoing spring flood potential. Pumps and dikes remain in place, but most roads have been reopened as water levels continue to drop along the Ottawa River and Lake of Two Mountains. Over 100mm (4 inches) of rain fell in April across the region, allowing for water levels to rise sharply late last month. Since May 1st, another 5-10mm has fallen, with 15-20mm possible this week. That being said, water levels remain stable in the Ontario portions of the river and are even lowering in some cases. The end result is that mitigation and observation efforts will remain as is for most municipalities in the greater Montreal area, but the forecast looks favourable at this time for a continued drop in in levels.

The gauge at Sainte-Anne-de-Bellevue remained in minor flood stage Monday morning, at 23,83 metres and slowly rising. However most other gauges on other portions of the Ottawa River upstream from Montreal are showing levels stable or even lowering.

Over the weekend the bridge to Île Mercier was reopened, as was Chemin de l'Anse à l'Orme late last week. Both had been clsoed since mid-April after being inundated by high water from Rivière des Prairies.

A second wave of high water possible for Montreal

Flood waters in Vaudreuil/Dorion and across southwestern Quebec have been lowering over the last week. However upcoming wet weather may force another surge of water down the Ottawa River towards Montreal over the upcoming week. (Photo: Ledy Quintero)

Flood warnings are in effect across the Ottawa River on the Ontario side of the border, as another wave of rising water is expected. The flood watch has remained in effect on the Quebec side from Pointe Fortune to Montreal. The recent dry weather has allowed water levels to drop across the region, but that will change with more rain in the forecast along with melting snow from the northern portion of the basin.

Water levels at the gauge in Sainte-Anne-de-Bellevue have dropped from 23.94 metres a little over a week ago down to 23.80 metres currently. This is back into the minor flood stage. 

Concern is on the rise that we may see another wave of high water throughout the Ottawa River Basin and its tributaries into the first week of May. Our dry weather is set to com to an end on Wednesday, with rainy weather forecast as a frontal boundary moves east. Both Ottawa and Montreal are forecasting 15-25mm of rain over the next 36 hours, with some regions in the Ottawa Valley expecting as much as 50mm.

Thankfully all flood mitigation efforts remain in place, with municipalities remaining vigilant and on high alert. It has been a welcome relief over the last week or so to see water levels lower in the Montreal region. The hope is that water levels will not reach those of earlier this month along the Ottawa River and Lake of Two Mountains. 

Our weather will not only turn wet, but sharply colder Thursday into the weekend, as an upper level low drifts over the region. Temperatures will remain in the single digits for highs through the weekend. Overnight lows will be close to the freezing point, with even a few flurries and scattered frost possible for some locations. 

One group that is happy to see some wet weather is SOPFEU, Quebec's wildfire management agency has been dealing with tinder dry conditions in our forests. Despite the flood threat, many regions have had very high fire danger, with burn bans in effect for several municipalities. The wet weather should alleviate that threat for the short-term.