Montreal weather by month
Montreal runs from about -6°C in January to 23°C in July, with August the wettest month at 218 mm.
warmest month
July
23°C
coolest month
January
-6°C
wettest month
August
218 mm
worst air month
February
16 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -6°C | 70 mm | 129 h | 13 |
| February | -4°C | 24 mm | 211 h | 16 |
| March | 1°C | 69 mm | 229 h | 11 |
| April | 7°C | 130 mm | 238 h | 11 |
| May | 16°C | 76 mm | 336 h | 9 |
| June | 20°C | 152 mm | 310 h | 12 |
| July | 23°C | 127 mm | 369 h | 14 |
| August | 21°C | 218 mm | 298 h | 13 |
| September | 18°C | 56 mm | 293 h | 11 |
| October | 11°C | 41 mm | 257 h | 7 |
| November | 5°C | 58 mm | 168 h | 8 |
| December | -5°C | 88 mm | 122 h | 9 |
About 2,960 hours of sun a year. Roughly 112 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-23. Full method, licences and the list of sources we rejected are on the methodology page.