Montréal weather in August
In August, Montréal has daytime highs averaging 24 °C, nights around 16 °C, with 12 wet days. Figures are 1991–2020 climate normals.
- 23.6°C Average high
- 15.5°C Average low
- 12days Wet days
- 100mm Rainfall
- 14h Daylight
Daily temperatures through August
How August develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 August | 24.3 °C | 16.3 °C | 41 % |
| 11–20 August | 23.7 °C | 15.7 °C | 38 % |
| 21–31 August | 22.7 °C | 14.6 °C | 34 % |
- Average highs fall from 24.3 °C early in August to 22.7 °C by the end of it.
- Rain is most likely over days 1–10 of August (41 % of days) and least likely over days 21–31 (34 %).
What to expect
| Measure | Typical August | Share of the month |
|---|---|---|
| Days above 25 °C | 9.5 of 31 | 31 % |
| Days above 30 °C | 0.5 of 31 | 2 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 12 of 31 | 37 % |
Conditions in August
| Measure | Average |
|---|---|
| Mean temperature | 19 °C |
| Record high (1991–2020) | 33 °C |
| Record low (1991–2020) | 8.3 °C |
| Relative humidity | 73 % |
| Wind speed | 16 km/h |
| Cloud cover | 54 % |
Where Montréal ranks in August
| Ranking | Position | Value |
|---|---|---|
| The coolest places in North America in August | 28thof 50 | 24 °C |
| Places with the best weather in North America in August | 31stof 50 | 86/100 |
August compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| June | 22.4 °C | 106 mm | 61 % |
| July | 24.6 °C | 101 mm | 55 % |
| August | 23.6 °C | 100 mm | 54 % |
| September | 19.5 °C | 98 mm | 55 % |
| October | 11.9 °C | 112 mm | 63 % |
See all twelve months for Montréal
- August is the 2nd warmest month here.
- It is the 8th driest month of the year.
- It ranks 1st for least cloud cover.
- Days last about 14 hours from sunrise to sunset.
- It rains on 12 of 31 days — 37 % of the month.
- Nights are about 8.1 °C cooler than the middle of the day.
- The hottest August day on record since 1991 reached 33 °C, 9.6 °C above the usual daytime high.
Nearby destinations in August
QuestionsAugust in Montréal, answered
How warm is Montréal in August?
Daily highs average 24 °C and nights fall to about 16 °C, a spread of 8.1 °C between afternoon and dawn. That makes August the 2nd warmest month of the year here.
Does it rain much in Montréal in August?
August averages 100 mm of rain, spread over about 12 of the 31 days — 37 % of the month. Cloud cover averages 54 % of the sky.
How long are the days in August?
Montréal averages 14 hours between sunrise and sunset in August. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.