Lyon weather by month
Lyon runs from about 3°C in December to 23°C in August, with September the wettest month at 202 mm.
warmest month
August
23°C
coolest month
December
3°C
wettest month
September
202 mm
worst air month
December
19 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 4°C | 57 mm | 135 h | 15 |
| February | 7°C | 73 mm | 156 h | 11 |
| March | 10°C | 143 mm | 243 h | 15 |
| April | 11°C | 107 mm | 292 h | 9 |
| May | 15°C | 154 mm | 299 h | 7 |
| June | 19°C | 104 mm | 336 h | 7 |
| July | 22°C | 116 mm | 396 h | 5 |
| August | 23°C | 49 mm | 388 h | 8 |
| September | 16°C | 202 mm | 272 h | 7 |
| October | 15°C | 122 mm | 235 h | 12 |
| November | 8°C | 58 mm | 169 h | 11 |
| December | 3°C | 57 mm | 160 h | 19 |
About 3,081 hours of sun a year. Roughly 124 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.