Lille weather by month
Lille runs from about 4°C in January to 20°C in August, with September the wettest month at 115 mm.
warmest month
August
20°C
coolest month
January
4°C
wettest month
September
115 mm
worst air month
March
17 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 4°C | 58 mm | 122 h | 12 |
| February | 8°C | 111 mm | 79 h | 9 |
| March | 9°C | 90 mm | 187 h | 17 |
| April | 11°C | 90 mm | 253 h | 12 |
| May | 14°C | 110 mm | 300 h | 11 |
| June | 15°C | 64 mm | 332 h | 8 |
| July | 18°C | 78 mm | 323 h | 7 |
| August | 20°C | 78 mm | 311 h | 8 |
| September | 16°C | 115 mm | 248 h | 7 |
| October | 13°C | 75 mm | 184 h | 10 |
| November | 8°C | 64 mm | 100 h | 9 |
| December | 6°C | 52 mm | 65 h | 13 |
About 2,504 hours of sun a year. Roughly 99 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 2026-05-24. Full method, licences and the list of sources we rejected are on the methodology page.