Bern weather by month
Bern runs from about 1°C in December to 20°C in August, with May the wettest month at 161 mm.
warmest month
August
20°C
coolest month
December
1°C
wettest month
May
161 mm
worst air month
March
13 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 2°C | 103 mm | 154 h | 10 |
| February | 5°C | 59 mm | 174 h | 7 |
| March | 7°C | 109 mm | 228 h | 13 |
| April | 9°C | 101 mm | 264 h | 10 |
| May | 13°C | 161 mm | 292 h | 6 |
| June | 17°C | 158 mm | 315 h | 6 |
| July | 19°C | 120 mm | 376 h | 5 |
| August | 20°C | 66 mm | 355 h | 8 |
| September | 13°C | 157 mm | 248 h | 6 |
| October | 11°C | 126 mm | 205 h | 9 |
| November | 4°C | 91 mm | 203 h | 9 |
| December | 1°C | 103 mm | 160 h | 12 |
About 2,974 hours of sun a year. Roughly 136 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 2026-05-25. Full method, licences and the list of sources we rejected are on the methodology page.