Brussels weather by month
Brussels runs from about 3°C in January to 20°C in August, with February the wettest month at 112 mm.
warmest month
August
20°C
coolest month
January
3°C
wettest month
February
112 mm
worst air month
March
18 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 3°C | 63 mm | 133 h | 14 |
| February | 8°C | 112 mm | 103 h | 9 |
| March | 9°C | 96 mm | 185 h | 18 |
| April | 11°C | 96 mm | 270 h | 12 |
| May | 15°C | 107 mm | 276 h | 10 |
| June | 16°C | 98 mm | 320 h | 8 |
| July | 18°C | 96 mm | 336 h | 8 |
| August | 20°C | 54 mm | 328 h | 8 |
| September | 16°C | 100 mm | 259 h | 7 |
| October | 13°C | 71 mm | 184 h | 10 |
| November | 7°C | 70 mm | 99 h | 10 |
| December | 6°C | 66 mm | 76 h | 13 |
About 2,569 hours of sun a year. Roughly 104 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.