August is one of the warmer months of the year in Montréal, with average highs near 25.9°C and lows around 15.4°C (mean 20.7°C). It is a relatively wet time of year, averaging 96 mm of rainfall and 73% relative humidity across the period.
August is one of the warmer months of the year in Montréal. Across 45 years of records, the warmest August in Montréal was 2021 — when the month averaged 24.3°C — while the coldest was 1982 at 17.8°C. Typical August days reach 25.9°C with nights near 15.4°C. The long-term trend is warming, about 0.5°C per decade.
August is a relatively wet time of year in Montréal, averaging 96 mm of rainfall. The wettest August on record was 2024 with 171 mm, while the driest was 2002 at 34 mm.
Relative humidity in Montréal during August averages 73%. The most humid August was 2008 at 80%, and the least humid was 2025 at 62%.
August receives about 5 kWh/m²/day of solar energy in Montréal. The sunniest August was 2002 at 5.6 kWh/m²/day, and the cloudiest was 1988 at 4.4.
Average wind speed in Montréal during August is 2.5 m/s. The windiest Augusts were 1982 and 1992 at 2.9 m/s, while the calmest were 2008 and 2014 at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.6°C | 20.5°C | 20.7°C | 21.2°C | 21.7°C | +2.1°C |
| Avg High | 25.0°C | 25.9°C | 25.8°C | 26.3°C | 27.0°C | +2°C |
| Avg Low | 14.2°C | 15.0°C | 15.5°C | 16.1°C | 16.5°C | +2.3°C |
| Avg Rain | 109 mm | 82 mm | 97 mm | 98 mm | 98 mm | -10 mm |
August temperatures in Montréal have risen by about 2.1°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 5.2°C (1982) to a record high of 36.4°C (2025).
Rainfall in August is a relatively wet time of year, averaging 96 mm, with a wettest year of 171 mm.
One of the best times to visit Montréal
August is one of the best times to visit Montréal. Expect days averaging 25.9°C and nights around 15.4°C (mean 20.7°C) — warmer than Montréal's yearly average — with higher rainfall (96 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 27.9°C | 21.8°C | 15.8°C | 36.4°C | 9.6°C | 57 mm | 62% | 2.4 m/s | 5.4 |
| 2024 🌧️ | 25.9°C | 20.9°C | 16.0°C | 32.9°C | 9.7°C | 171 mm | 77% | 2.3 m/s | 4.5 |
| 2023 | 24.8°C | 19.9°C | 15.0°C | 27.9°C | 9.2°C | 106 mm | 76% | 2.4 m/s | 4.6 |
| 2022 | 27.4°C | 22.0°C | 16.5°C | 34.0°C | 10.8°C | 92 mm | 70% | 2.3 m/s | 4.9 |
| 2021 🔥 | 29.6°C | 24.3°C | 19.0°C | 34.5°C | 13.1°C | 39 mm | 67% | 2.5 m/s | 4.9 |
| 2020 | 26.5°C | 21.5°C | 16.6°C | 32.6°C | 10.0°C | 126 mm | 71% | 2.6 m/s | 5.1 |
| 2019 | 26.7°C | 21.1°C | 15.5°C | 31.6°C | 11.4°C | 74 mm | 70% | 2.6 m/s | 5.4 |
| 2018 | 28.4°C | 23.2°C | 17.9°C | 32.8°C | 11.3°C | 65 mm | 72% | 2.5 m/s | 4.9 |
| 2017 | 24.1°C | 19.5°C | 14.9°C | 28.0°C | 8.7°C | 82 mm | 77% | 2.4 m/s | 5.3 |
| 2016 | 27.7°C | 22.5°C | 17.4°C | 33.4°C | 12.0°C | 153 mm | 73% | 2.7 m/s | 5.1 |
| 2015 | 26.3°C | 21.3°C | 16.4°C | 32.0°C | 11.6°C | 92 mm | 75% | 2.5 m/s | 5 |
| 2014 | 24.6°C | 19.8°C | 15.1°C | 29.7°C | 10.1°C | 87 mm | 77% | 2.2 m/s | 5.1 |
| 2013 | 25.4°C | 20.2°C | 14.9°C | 29.9°C | 9.4°C | 89 mm | 74% | 2.6 m/s | 5.2 |
| 2012 | 27.9°C | 22.5°C | 17.0°C | 33.8°C | 10.3°C | 72 mm | 68% | 2.7 m/s | 5.1 |
| 2011 | 25.4°C | 20.7°C | 16.0°C | 30.1°C | 11.2°C | 158 mm | 77% | 2.5 m/s | 4.8 |
| 2010 | 26.1°C | 20.9°C | 15.8°C | 33.6°C | 9.9°C | 110 mm | 75% | 2.6 m/s | 5.1 |
| 2009 | 25.3°C | 20.7°C | 16.1°C | 31.9°C | 8.4°C | 76 mm | 77% | 2.5 m/s | 5 |
| 2008 | 23.9°C | 19.3°C | 14.8°C | 28.7°C | 9.5°C | 109 mm | 80% | 2.2 m/s | 5 |
| 2007 | 26.1°C | 20.3°C | 14.4°C | 32.2°C | 8.5°C | 83 mm | 72% | 2.5 m/s | 5.2 |
| 2006 | 23.8°C | 19.0°C | 14.1°C | 30.9°C | 8.5°C | 132 mm | 77% | 2.6 m/s | 5.2 |
| 2005 | 27.6°C | 22.2°C | 16.8°C | 31.8°C | 10.1°C | 120 mm | 70% | 2.5 m/s | 5 |
| 2004 | 23.9°C | 19.2°C | 14.4°C | 29.1°C | 7.7°C | 111 mm | 80% | 2.4 m/s | 4.6 |
| 2003 | 26.1°C | 21.5°C | 16.8°C | 30.3°C | 9.6°C | 89 mm | 76% | 2.6 m/s | 4.6 |
| 2002 | 27.5°C | 21.8°C | 16.1°C | 34.5°C | 10.3°C | 34 mm | 70% | 2.6 m/s | 5.6 |
| 2001 | 28.9°C | 23.0°C | 17.1°C | 34.7°C | 11.6°C | 90 mm | 66% | 2.7 m/s | 5.3 |
| 2000 | 24.4°C | 19.5°C | 14.5°C | 29.1°C | 9.1°C | 121 mm | 79% | 2.7 m/s | 4.7 |
| 1999 | 25.7°C | 20.3°C | 14.9°C | 31.1°C | 9.9°C | 62 mm | 67% | 2.5 m/s | 5.1 |
| 1998 | 26.4°C | 21.3°C | 16.2°C | 32.0°C | 10.3°C | 87 mm | 72% | 2.3 m/s | 5.1 |
| 1997 | 25.0°C | 19.7°C | 14.4°C | 32.1°C | 11.1°C | 91 mm | 70% | 2.5 m/s | 5 |
| 1996 | 26.8°C | 20.9°C | 15.1°C | 31.3°C | 9.7°C | 36 mm | 70% | 2.5 m/s | 5.3 |
| 1995 | 27.1°C | 21.1°C | 15.1°C | 33.0°C | 9.5°C | 85 mm | 67% | 2.8 m/s | 5.3 |
| 1994 | 24.5°C | 19.1°C | 13.7°C | 30.0°C | 8.2°C | 72 mm | 74% | 2.7 m/s | 5 |
| 1993 | 26.7°C | 21.5°C | 16.2°C | 31.5°C | 10.9°C | 63 mm | 73% | 2.4 m/s | 5.2 |
| 1992 | 24.1°C | 18.9°C | 13.7°C | 30.3°C | 8.4°C | 94 mm | 76% | 2.9 m/s | 4.7 |
| 1991 | 27.0°C | 21.5°C | 15.9°C | 32.1°C | 9.3°C | 113 mm | 71% | 2.8 m/s | 4.9 |
| 1990 | 26.0°C | 20.6°C | 15.2°C | 30.4°C | 8.7°C | 113 mm | 76% | 2.4 m/s | 5.2 |
| 1989 | 24.7°C | 19.4°C | 14.0°C | 30.1°C | 6.1°C | 118 mm | 73% | 2.5 m/s | 5.1 |
| 1988 | 26.2°C | 21.1°C | 15.9°C | 33.6°C | 8.0°C | 127 mm | 74% | 2.7 m/s | 4.4 |
| 1987 | 25.2°C | 19.3°C | 13.4°C | 33.1°C | 7.3°C | 58 mm | 68% | 2.6 m/s | 5 |
| 1986 | 23.0°C | 18.0°C | 13.0°C | 28.1°C | 5.2°C | 141 mm | 79% | 2.7 m/s | 4.8 |
| 1985 | 25.0°C | 19.3°C | 13.5°C | 31.0°C | 7.8°C | 69 mm | 70% | 2.5 m/s | 4.7 |
| 1984 | 26.8°C | 21.5°C | 16.1°C | 31.9°C | 8.5°C | 115 mm | 73% | 2.5 m/s | 5.4 |
| 1983 | 26.3°C | 20.9°C | 15.5°C | 30.4°C | 8.5°C | 79 mm | 71% | 2.4 m/s | — |
| 1982 ❄️ | 23.2°C | 17.8°C | 12.4°C | 28.4°C | 5.2°C | 128 mm | 72% | 2.9 m/s | — |
| 1981 | 24.2°C | 19.2°C | 14.1°C | 28.8°C | 8.1°C | 143 mm | 78% | 2.3 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 25.9°C with lows near 15.4°C (mean 20.7°C), based on 45 years of NASA POWER data.
August averages 96 mm of rainfall in Montréal, a relatively wet time of year. The wettest on record was 171 mm in 2024.
The hottest August reached 36.4°C in 2025. The coldest dipped to 5.2°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 2.1°C. Daytime highs moved from 25.1°C to 27.1°C and overnight lows from 14.3°C to 16.5°C over the same span.
August is one of the warmer months of the year in Montréal and a relatively wet time of year, so plan for around 25.9°C daytime highs and 15.4°C at night.
Not quite — August is the 11th coolest month in Montréal, averaging 20.7°C.
For August in Montréal, pack light layers you can adjust through the day, with typical highs of 25.9°C and lows of 15.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 73% — moderately humid.
Average wind speed in August is 2.5 m/s. The windiest August on record averaged 2.9 m/s (1982).
The wettest August on record was 2024 with 171 mm. On average, August sees 96 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Montréal behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
