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.