Weather in Montréal

July is the warmest month (average 21.4°C, high 26.2°C) and January is the coolest (average -11.7°C, low -16.9°C). That 33.1°C swing in monthly averages is the first thing to plan around in Montréal.

Rain is wet season runs from April to August, inside an annual total of 1086 mm. The wettest month is October at 114 mm; the driest is February at 68 mm. Montréal is in Canada at 45.5°N. The 2001–2020 NASA POWER daily record describes a continental climate with a wide temperature swing. On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are June, July, and August.

Best months to visit Montréal

The three months with the highest comfort score are June, July, and August: June (18.2°C average, 109 mm, 79% humidity); July (21.4°C average, 95 mm, 77% humidity); August (21.0°C average, 98 mm, 74% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the wet season itself — fewer crowds, greener landscape, heavier rain — aim at April–August instead of the score.

Temperature through the year

Montréal has a 33.1°C gap between its coolest monthly average (-11.7°C in January) and its warmest (21.4°C in July). That is a northern-hemisphere pattern.

Mean high across all twelve months is 11.0°C and mean low is 1.3°C. These are 20-year grid averages, so a city station can read a few degrees warmer or cooler.

Rainfall pattern

The wet season in Montréal starts in April and ends in August (April, May, June, July, and August). October is the core of it at 114 mm. February is the other extreme, with 68 mm.

A rainy day here is a day with at least 1 mm in the NASA POWER series. October averages 14 such days; February averages 12.

Distinctive months in Montréal

January is the coolest month, with lows around -16.9°C and highs near -6.5°C. Rainfall is 72 mm. February is the driest month, averaging only 68 mm across 12 rainy days. Highs sit near -4.6°C. March stands apart from the months beside it: 1.1°C / -8.5°C and 76 mm. The wet season opens in April. Expect 95 mm and 13 rainy days, with nights around 0.2°C. In May, Montréal averages 18.1°C by day and 7.5°C at night, with 93 mm of rain. June brings 109 mm and 16 rainy days; temperatures run from 13.4°C to 22.9°C.

Peak heat arrives in July: 26.2°C by day, 16.6°C at night, and 77% humidity. By August the wet season is ending. Montréal still sees about 98 mm, but the next month is usually leaner. In September, Montréal averages 22.4°C by day and 11.4°C at night, with 88 mm of rain. October is the wettest month — 114 mm and 14 rainy days, with 81% humidity. November: 5.3°C high, -2.2°C low, 81 mm rain, 86% humidity. December stands apart from the months beside it: -2.6°C / -11.2°C and 98 mm.

How Montréal compares inside Canada

Toronto is about 502 km away: Montréal is about as warm as Toronto at the hot peak and 312 mm wetter over the year than Toronto. Toronto’s wettest month is July (75 mm) versus October here.

Calgary is about 3019 km away: Montréal is 4.9°C warmer than Calgary in its hottest month and 540 mm wetter over the year than Calgary. Calgary’s wettest month is June (115 mm) versus October here.