Fewer days reach 25 degrees in Chavenay than in 79% of mainland French towns
January mornings start at about 1.9°C. The gap between a January night and a July afternoon is 23°C. By rainfall alone, it ranks drier than 74% of mainland French towns. Windscreens need scraping on about 39 mornings a year, the nights the air drops below 0°C.
These are the figures of Météo-France’s Trappes station, 9.1 km south.
A year in Chavenay at a glance
Each month’s typical high and low in °C, at the Trappes station.
What a year in Chavenay feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Trappes.
About 686 mm of rain a year
December is the wettest month and September the driest. About 18 days a year bring 10 mm or more. 7th wettest of 95 towns of 2,500+ in Yvelines.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Trappes
39 frosts and 42 days of 25°C a year
On about 39 nights a year the air drops to 0°C or below, and on about 5 days it stays below freezing all day. About 42 days a year reach 25°C, and 9 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Trappes: a frost is a night of 0°C or below, a summer day (jour d’été) 25°C or more, a hot day (forte chaleur) 30°C or more.
The Météo-France station at Trappes
Trappes is 9.1 km south of Chavenay. Every figure on this page is the station’s, not a measurement in Chavenay itself.
| Station (Météo-France number) | Trappes (78621001) |
| Distance from the town | 9.1 km south |
| Station altitude | 167 m |
| Town altitude (its center) | 95 m |
| Period | 1991–2020 |
| Sunshine measured at | the same station |
TownRatings matches each commune to one station with at least 24 years of temperature and rain records: the nearest, counting every 100 m of height difference as 10 km, never across the sea.
How Chavenay compares
Against the 4,385 towns of 2,500 or more in mainland France, each read from its own matched station. The dots are the other towns of 2,500+ in Yvelines.
Nearby towns’ climate
The nearest towns of 2,500+ within 29 km. Where a neighbor uses the same station its figures are the same: the differences you’d feel over a few kilometers aren’t in the normals.
| Town | Station | July high | January low | Rain a year |
|---|---|---|---|---|
| Chavenay | Trappes | 24.6°C | 1.9°C | 686 mm |
| Saint-Nom-la-Bretèche 2.4 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
| Feucherolles 2.4 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
| Villepreux 3.1 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
| Les Clayes-sous-Bois 3.5 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
| Plaisir 4.5 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
| Noisy-le-Roi 5.6 km | same station | 24.6°C about the same | 1.9°C about the same | 686 mm |
Chavenay weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Trappes station.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 6.8°C | 1.9°C | 4.3°C | 56 mm | 57 |
| February | 8.0°C | 1.8°C | 4.9°C | 50 mm | 81 |
| March | 11.9°C | 3.9°C | 7.9°C | 50 mm | 134 |
| April | 15.4°C | 6.0°C | 10.7°C | 50 mm | 176 |
| May | 18.8°C | 9.4°C | 14.1°C | 66 mm | 202 |
| June | 22.1°C | 12.5°C | 17.3°C | 57 mm | 210 |
| July | 24.6°C | 14.4°C | 19.5°C | 56 mm | 222 |
| August | 24.6°C | 14.2°C | 19.4°C | 56 mm | 216 |
| September | 20.7°C | 11.3°C | 16.0°C | 50 mm | 177 |
| October | 15.8°C | 8.5°C | 12.2°C | 62 mm | 117 |
| November | 10.4°C | 4.8°C | 7.6°C | 61 mm | 68 |
| December | 7.2°C | 2.4°C | 4.8°C | 72 mm | 55 |
| Year | 15.5°C | 7.6°C | 11.6°C | 686 mm | 1,714 |
Where Chavenay’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Trappes, 9.1 km away: statistics for 1991–2020.
- Which station: among stations with at least 24 of the 30 years of temperature and rain, the nearest to the commune’s population-weighted center, counting each 100 m of height difference as 10 km; mainland towns use mainland stations and each overseas département its own.
- Altitudes: the town’s from IGN’s RGE ALTI® at its population-weighted center; the station’s from Météo-France.
- Sunshine: the nearest station with at least 10 years of sunshine records, Trappes, 9.1 km away.
- Comparisons: every town of 2,500 or more in mainland France, read the same way; the dots are the towns of 2,500+ in Yvelines.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Chavenay’s climate
How warm does Chavenay get in summer?
July is the warmest month, with average highs of 24.6°C. About 42 days a year reach 25°C, fewer than 79% of mainland French towns, and about 9 reach 30°C.
How cold does Chavenay get in winter?
February nights average 1.8°C. The air drops to 0°C or below on about 39 nights a year, and about 5 days a year stay below freezing all day.
How much rain does Chavenay get?
About 686 mm a year, less than 74% of mainland French towns. December is the wettest month (72 mm) and September the driest (50 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Trappes (9.1 km away), averages 1,714 hours of sunshine a year.
Are these figures for Chavenay itself?
No: they are the normals of the Météo-France station matched to Chavenay, Trappes, 9.1 km away. France publishes its climate normals by station, not by commune; a valley, a hill or the sea can make a difference over a few kilometers.
Where do these figures come from?
Météo-France’s fiches climatologiques: 30-year averages (1991–2020) for each of its long-running stations, published as open data since 2024. They are normals, not a forecast.
Source: Météo-France, fiches climatologiques, 1991–2020 statistics (station TRAPPES, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Chavenay →
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.