Rainfall in Boissy-le-Sec trails that of 82% of mainland French towns: 654 mm a year
The depth of winter brings overnight lows near 1.5°C. By frosts alone, it ranks colder than 70% of mainland French towns. Winter and summer sit 25°C apart. Wet days, with 1 mm of rain or more, come about 114 times a year.
These are the figures of Météo-France’s Dourdan station, 8.5 km north-west.
A year in Boissy-le-Sec at a glance
Each month’s typical high and low in °C, at the Dourdan station.
What a year in Boissy-le-Sec feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Dourdan.
About 654 mm of rain a year
May is the wettest month and April the driest. About 17 days a year bring 10 mm or more. 37th wettest of 96 towns of 2,500+ in Essonne.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Trappes
A frosty town: 51 frosts and 53 days of 25°C a year
On about 51 nights a year the air drops to 0°C or below, and on about 4 days it stays below freezing all day. About 53 days a year reach 25°C, and 14 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Dourdan: 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 Dourdan
Dourdan is 8.5 km north-west of Boissy-le-Sec. Every figure on this page is the station’s, not a measurement in Boissy-le-Sec itself.
| Station (Météo-France number) | Dourdan (91200002) |
| Distance from the town | 8.5 km north-west |
| Station altitude | 116 m |
| Town altitude (its center) | 149 m |
| Period | 1991–2020 |
| Sunshine measured at | Trappes, 33 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 Boissy-le-Sec 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 Essonne.
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 |
|---|---|---|---|---|
| Boissy-le-Sec | Dourdan | 25.7°C | 1.5°C | 654 mm |
| Étampes 7.3 km | Courdimanche | 26.3°C 0.6°C warmer | 1.4°C about the same | 595 mm |
| Étréchy 7.4 km | Brétigny | 26.0°C about the same | 1.7°C about the same | 629 mm |
| Dourdan 7.6 km | same station | 25.7°C about the same | 1.5°C about the same | 654 mm |
| Saint-Chéron 8.1 km | Fontenay-lès-B. | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Morigny-Champigny 8.5 km | Courdimanche | 26.3°C 0.6°C warmer | 1.4°C about the same | 595 mm |
| Breuillet 12 km | Fontenay-lès-B. | 26.1°C about the same | 1.5°C about the same | 696 mm |
Boissy-le-Sec weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Dourdan station; sunshine at Trappes.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 6.9°C | 1.5°C | 4.2°C | 52 mm | 57 |
| February | 8.2°C | 1.2°C | 4.7°C | 48 mm | 81 |
| March | 12.4°C | 3.1°C | 7.8°C | 50 mm | 134 |
| April | 16.0°C | 4.9°C | 10.5°C | 44 mm | 176 |
| May | 19.4°C | 8.3°C | 13.9°C | 69 mm | 202 |
| June | 23.0°C | 11.4°C | 17.2°C | 54 mm | 210 |
| July | 25.7°C | 13.3°C | 19.5°C | 52 mm | 222 |
| August | 25.6°C | 13.1°C | 19.3°C | 57 mm | 216 |
| September | 21.5°C | 10.1°C | 15.9°C | 48 mm | 177 |
| October | 16.4°C | 7.7°C | 12.0°C | 55 mm | 117 |
| November | 10.8°C | 4.4°C | 7.6°C | 61 mm | 68 |
| December | 7.4°C | 2.0°C | 4.7°C | 66 mm | 55 |
| Year | 16.1°C | 6.8°C | 11.4°C | 654 mm | 1,714 |
Where Boissy-le-Sec’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Dourdan, 8.5 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, 33 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 Essonne.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Boissy-le-Sec’s climate
How warm does Boissy-le-Sec get in summer?
July is the warmest month, with average highs of 25.7°C. About 53 days a year reach 25°C, fewer than 64% of mainland French towns, and about 14 reach 30°C.
How cold does Boissy-le-Sec get in winter?
February nights average 1.2°C. The air drops to 0°C or below on about 51 nights a year, and about 4 days a year stay below freezing all day.
How much rain does Boissy-le-Sec get?
About 654 mm a year, less than 82% of mainland French towns. May is the wettest month (69 mm) and April the driest (44 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Trappes (33 km away), averages 1,714 hours of sunshine a year.
Are these figures for Boissy-le-Sec itself?
No: they are the normals of the Météo-France station matched to Boissy-le-Sec, Dourdan, 8.5 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 DOURDAN, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Boissy-le-Sec →
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.