Rainfall in Saclay trails that of 76% of mainland French towns: 677 mm a year
January nights here settle around 1.6°C. A year here swings 24°C from midwinter lows to midsummer highs. Warm afternoons come less often than in 71% of mainland French towns. An umbrella earns its place on about 115 days a year with 1 mm of rain or more.
Figures from Météo-France’s Toussus-le-Noble station, 4.4 km west.
A year in Saclay at a glance
Each month’s typical high and low in °C, at the Toussus-le-Noble station.
What a year in Saclay feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Toussus-le-Noble.
About 677 mm of rain a year
May is the wettest month and February the driest. About 18 days a year bring 10 mm or more. 23rd wettest of 96 towns of 2,500+ in Essonne.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Trappes
46 frosts and 49 days of 25°C a year
On about 46 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 11 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Toussus-le-Noble: 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 Toussus-le-Noble
Toussus-le-Noble is 4.4 km west of Saclay. Every figure on this page is the station’s, not a measurement in Saclay itself.
| Station (Météo-France number) | Toussus-le-Noble (78620001) |
| Distance from the town | 4.4 km west |
| Station altitude | 154 m |
| Town altitude (its center) | 148 m |
| Period | 1991–2020 |
| Sunshine measured at | Trappes, 12 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 Saclay 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 |
|---|---|---|---|---|
| Saclay | Toussus-le-Noble | 25.2°C | 1.6°C | 677 mm |
| Jouy-en-Josas 2.8 km | same station | 25.2°C about the same | 1.6°C about the same | 677 mm |
| Bièvres 3.4 km | Paris-Montsouris | 25.7°C 0.5°C warmer | 3.2°C 1.6°C milder | 634 mm |
| Igny 3.9 km | Paris-Montsouris | 25.7°C 0.5°C warmer | 3.2°C 1.6°C milder | 634 mm |
| Vélizy-Villacoublay 4.9 km | same station | 25.2°C about the same | 1.6°C about the same | 677 mm |
| Buc 5.1 km | same station | 25.2°C about the same | 1.6°C about the same | 677 mm |
| Orsay 5.3 km | Fontenay-lès-B. | 26.1°C 0.9°C warmer | 1.5°C about the same | 696 mm |
Saclay weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Toussus-le-Noble station; sunshine at Trappes.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 6.7°C | 1.6°C | 4.2°C | 55 mm | 57 |
| February | 8.0°C | 1.4°C | 4.7°C | 47 mm | 81 |
| March | 12.1°C | 3.5°C | 7.8°C | 50 mm | 134 |
| April | 15.8°C | 5.5°C | 10.6°C | 50 mm | 176 |
| May | 19.3°C | 8.9°C | 14.1°C | 68 mm | 202 |
| June | 22.8°C | 12.1°C | 17.4°C | 55 mm | 210 |
| July | 25.2°C | 13.9°C | 19.6°C | 53 mm | 222 |
| August | 25.2°C | 13.6°C | 19.4°C | 58 mm | 216 |
| September | 21.0°C | 10.6°C | 15.8°C | 52 mm | 177 |
| October | 15.9°C | 8.0°C | 11.9°C | 61 mm | 117 |
| November | 10.4°C | 4.5°C | 7.4°C | 61 mm | 68 |
| December | 7.1°C | 2.1°C | 4.6°C | 66 mm | 55 |
| Year | 15.8°C | 7.1°C | 11.5°C | 677 mm | 1,714 |
Where Saclay’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Toussus-le-Noble, 4.4 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, 12 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 Saclay’s climate
How warm does Saclay get in summer?
July is the warmest month, with average highs of 25.2°C. About 49 days a year reach 25°C, fewer than 71% of mainland French towns, and about 11 reach 30°C.
How cold does Saclay get in winter?
February nights average 1.4°C. The air drops to 0°C or below on about 46 nights a year, and about 5 days a year stay below freezing all day.
How much rain does Saclay get?
About 677 mm a year, less than 76% of mainland French towns. May is the wettest month (68 mm) and February the driest (47 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Trappes (12 km away), averages 1,714 hours of sunshine a year.
Are these figures for Saclay itself?
No: they are the normals of the Météo-France station matched to Saclay, Toussus-le-Noble, 4.4 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 TOUSSUS LE NOBLE, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Saclay →
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.