Ice on the ground: Saint-Forget sees more frosts than 73% of mainland French towns
On a normal July day the thermometer tops out near 25.1°C. Its July afternoons stay fresher than in 70% of mainland French towns. Of all months, December brings the most rain and April the least. Picnics, hikes and garden evenings come into their own from May to September, with highs of 19–25°C.
These are the figures of Météo-France’s Choisel station, 3.3 km south.
A year in Saint-Forget at a glance
Each month’s typical high and low in °C, at the Choisel station.
What a year in Saint-Forget feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Choisel.
About 709 mm of rain a year
December is the wettest month and April the driest. About 20 days a year bring 10 mm or more. The wettest of 95 towns of 2,500+ in Yvelines.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Trappes
A frosty town: 53 frosts and 49 days of 25°C a year
On about 53 nights a year the air drops to 0°C or below, and on about 5 days it stays below freezing all day. About 49 days a year reach 25°C, and 13 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Choisel: 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 Choisel
Choisel is 3.3 km south of Saint-Forget. Every figure on this page is the station’s, not a measurement in Saint-Forget itself.
| Station (Météo-France number) | Choisel (78162001) |
| Distance from the town | 3.3 km south |
| Station altitude | 176 m |
| Town altitude (its center) | 165 m |
| Period | 1991–2019 (the station’s own record) |
| Sunshine measured at | Trappes, 6.7 km away |
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 Saint-Forget 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 |
|---|---|---|---|---|
| Saint-Forget | Choisel | 25.1°C | 1.3°C | 709 mm |
| Chevreuse 3.5 km | same station | 25.1°C about the same | 1.3°C about the same | 709 mm |
| Le Mesnil-Saint-Denis 4.5 km | Trappes | 24.6°C 0.5°C cooler | 1.9°C 0.6°C milder | 686 mm |
| Saint-Rémy-lès-Chevreuse 5.5 km | Toussus-le-Noble | 25.2°C about the same | 1.6°C about the same | 677 mm |
| La Verrière 5.6 km | Trappes | 24.6°C 0.5°C cooler | 1.9°C 0.6°C milder | 686 mm |
| Voisins-le-Bretonneux 6.4 km | Trappes | 24.6°C 0.5°C cooler | 1.9°C 0.6°C milder | 686 mm |
| Magny-les-Hameaux 6.8 km | Toussus-le-Noble | 25.2°C about the same | 1.6°C about the same | 677 mm |
Saint-Forget weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Choisel station; sunshine at Trappes.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 6.7°C | 1.3°C | 4.0°C | 61 mm | 57 |
| February | 7.7°C | 1.0°C | 4.4°C | 52 mm | 81 |
| March | 11.9°C | 3.1°C | 7.5°C | 52 mm | 134 |
| April | 15.3°C | 5.0°C | 10.1°C | 49 mm | 176 |
| May | 19.2°C | 8.4°C | 13.8°C | 68 mm | 202 |
| June | 22.6°C | 11.4°C | 17.0°C | 62 mm | 210 |
| July | 25.1°C | 13.2°C | 19.2°C | 52 mm | 222 |
| August | 25.0°C | 13.0°C | 19.0°C | 56 mm | 216 |
| September | 20.8°C | 10.1°C | 15.4°C | 52 mm | 177 |
| October | 15.8°C | 7.4°C | 11.6°C | 66 mm | 117 |
| November | 10.4°C | 4.1°C | 7.2°C | 65 mm | 68 |
| December | 6.9°C | 1.6°C | 4.2°C | 76 mm | 55 |
| Year | 15.6°C | 6.6°C | 11.1°C | 709 mm | 1,714 |
Where Saint-Forget’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Choisel, 3.3 km away: statistics for 1991–2020 (the station’s own years, 1991–2019, where its record is shorter).
- 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, 6.7 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 Saint-Forget’s climate
How warm does Saint-Forget get in summer?
July is the warmest month, with average highs of 25.1°C. About 49 days a year reach 25°C, fewer than 70% of mainland French towns, and about 13 reach 30°C.
How cold does Saint-Forget get in winter?
February nights average 1.0°C. The air drops to 0°C or below on about 53 nights a year, and about 5 days a year stay below freezing all day.
How much rain does Saint-Forget get?
About 709 mm a year, less than 66% of mainland French towns. December is the wettest month (76 mm) and April the driest (49 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Trappes (6.7 km away), averages 1,714 hours of sunshine a year.
Are these figures for Saint-Forget itself?
No: they are the normals of the Météo-France station matched to Saint-Forget, Choisel, 3.3 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 CHOISEL, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Saint-Forget →
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.