Geneva weather by month
Geneva runs from about 3°C in December to 22°C in August, with May the wettest month at 166 mm.
warmest month
August
22°C
coolest month
December
3°C
wettest month
May
166 mm
worst air month
December
15 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 3°C | 116 mm | 158 h | 12 |
| February | 6°C | 78 mm | 191 h | 10 |
| March | 8°C | 90 mm | 242 h | 14 |
| April | 10°C | 94 mm | 298 h | 9 |
| May | 14°C | 166 mm | 314 h | 7 |
| June | 18°C | 148 mm | 339 h | 7 |
| July | 21°C | 81 mm | 402 h | 4 |
| August | 22°C | 54 mm | 387 h | 8 |
| September | 15°C | 155 mm | 252 h | 6 |
| October | 13°C | 133 mm | 239 h | 9 |
| November | 7°C | 85 mm | 223 h | 11 |
| December | 3°C | 112 mm | 180 h | 15 |
About 3,225 hours of sun a year. Roughly 132 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.