UPDATE August 12, 2025: Montreal is facing another oppressively hot day, with highs near 34°C but feeling closer to 41°C thanks to the humidity. Sunday’s extreme heat set a new record in Montreal—the mercury climbed to 34.4°C, beating the previous record of 32.8°C set in 1944.
When will it cool down in Montreal?
While the heat will peak on Tuesday, Wednesday's showers and cloudy skies will help cool things down, with a high of 26°C and a low of 19°C—the first time in days the temperature will drop below 20°C.
Last week, the weather networks forecasted a five-day heat wave for Montreal, beginning Friday and lasting through Tuesday.
There’s no time like the present to bookmark Montreal’s air-conditioned public places, swimming pools, local beaches and shaded green space.
What was the hottest summer in Montreal?
Environment Canada urges Canadians to take precautions during extreme heat.
This includes identifying whether you or those around you may be more vulnerable to heat-related illness, and checking in regularly—several times a day—on older adults, people living alone, and others at greater risk.
Be alert for early symptoms of heat exhaustion in yourself and others.
These can include headaches, dizziness, nausea, extreme tiredness, dark-coloured urine, and intense thirst.
If symptoms appear, stop all activity and start hydrating. Drink water frequently, even before you feel thirsty, to stay ahead of dehydration. Keep your living space cool by closing blinds, opening windows if it’s cooler outside, using fans or air conditioning, or relocating to a cooler area.
If your home stays hot, consider going to an air-conditioned public place like a cooling centre, library, community centre, or shaded green space.
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