Weather in Montreal in September 2025
Average weather
Average temperature in Montreal in September
The expected average maximum temperature in September is +23°C with a maximum of +32°C and a minimum of +7°C.
The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +23°C to +23°C.
Is Montreal warm or cold in September?
Montreal is typically mild in September.
Maximum temperatures go down compared to the previous month from +25°C to +21°C. The minimum temperature also goes down from +17°C to +12°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how September is compared to other months in Montreal:
Climate in Montreal in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +25°C | +21°C | +13°C | ||||
| Min. temperature | ||||||
| +6°C | -3°C | -6°C | ||||
| Max. temperature | ||||||
| +35°C | +34°C | +30°C | ||||
| Rainfall | ||||||
| 102 mm | 98 mm | 113 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 4 m/s | ||||
| Humidity | ||||||
| 71% | 73% | 73% | ||||
| Air pressure | ||||||
| 1014 HPa | 1016 HPa | 1015 HPa | ||||
| Sunny days | ||||||
| 6 | 7 | 5 | ||||
| Cloudy days | ||||||
| 8 | 9 | 9 | ||||
| Rainy days | ||||||
| 13 | 13 | 16 | ||||
| Snowy days | ||||||
| 0 | 0 | 1 | ||||
September weather is still as good as in August. It’s getting colder in September. From +25°C in the day, the average maximum temperature lowers to +21°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 102 mm to 98 mm. Humidity rises from 71% to 73%. The average wind speed doesn’t change much during September, staying around 3 m/s. The good news is there are likely to be more sunny days in September, from 6 to 7.
Next month (October) brings a further decline in the weather.
Wind
The average wind speed is 3 m/s getting up to 7 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Montreal is gradually decreasing during September, going from 3 m/s to 2 m/s over the course of the month.
Rain
How was the weather last September in Montreal?
Climate Change over Years
The climate in Montreal in September has not changed much over the last 43 years.
The average temperature was the lowest in 1980 (+10°C) and the highest in 2021 (+14°C). The driest year was 1985 with only 524 mm of rainfall, and the wettest year was 2023 with 2843 mm.
FAQ
Is September a good time to visit Montreal?
Can you sunbathe in Montreal in September?
Is Montreal rainy in September?
Is it sunny in Montreal in September?
Other cities in Canada
Monthly weather in Montreal
Source of the data
For this page, we’ve looked at the typical weather in Montreal, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.