Frost comes to Saint-Yon more often than to 72% of mainland French towns
In July the day’s top temperature is typically 26.1°C. Only 25°C separates winter nights from summer afternoons. By rainfall alone, it ranks drier than 69% of mainland French towns. Garden chairs stay out from May to September, the months with highs of 20–26°C.
These are the figures of Météo-France’s Fontenay-lès-B. station, 5.8 km north.
A year in Saint-Yon at a glance
Each month’s typical high and low in °C, at the Fontenay-lès-B. station.
What a year in Saint-Yon feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Fontenay-lès-B..
About 696 mm of rain a year
December is the wettest month and April the driest. About 18 days a year bring 10 mm or more. 14th wettest of 96 towns of 2,500+ in Essonne.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Orly
A frosty town: 53 frosts and 60 days of 25°C a year
On about 53 nights a year the air drops to 0°C or below, and on about 4 days it stays below freezing all day. About 60 days a year reach 25°C, and 16 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Fontenay-lès-B.: 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 Fontenay-lès-B.
Fontenay-lès-B. is 5.8 km north of Saint-Yon. Every figure on this page is the station’s, not a measurement in Saint-Yon itself.
| Station (Météo-France number) | Fontenay-lès-B. (91243001) |
| Distance from the town | 5.8 km north |
| Station altitude | 109 m |
| Town altitude (its center) | 85 m |
| Period | 1991–2020 |
| Sunshine measured at | Orly, 23 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-Yon 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 |
|---|---|---|---|---|
| Saint-Yon | Fontenay-lès-B. | 26.1°C | 1.5°C | 696 mm |
| Breuillet 1.3 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Boissy-sous-Saint-Yon 2.2 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Bruyères-le-Châtel 3.5 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Égly 3.9 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Saint-Chéron 4.6 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
| Ollainville 4.8 km | same station | 26.1°C about the same | 1.5°C about the same | 696 mm |
Saint-Yon weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Fontenay-lès-B. station; sunshine at Orly.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 7.3°C | 1.5°C | 4.4°C | 54 mm | 53 |
| February | 8.5°C | 1.2°C | 4.9°C | 49 mm | 85 |
| March | 12.6°C | 3.1°C | 7.9°C | 50 mm | 153 |
| April | 16.3°C | 5.0°C | 10.7°C | 48 mm | 203 |
| May | 20.1°C | 8.6°C | 14.3°C | 69 mm | 217 |
| June | 23.5°C | 11.6°C | 17.5°C | 58 mm | 224 |
| July | 26.1°C | 13.4°C | 19.8°C | 61 mm | 247 |
| August | 26.0°C | 13.2°C | 19.6°C | 63 mm | 221 |
| September | 21.8°C | 10.2°C | 16.0°C | 51 mm | 186 |
| October | 16.6°C | 7.7°C | 12.1°C | 61 mm | 117 |
| November | 10.9°C | 4.4°C | 7.6°C | 61 mm | 62 |
| December | 7.6°C | 2.1°C | 4.8°C | 71 mm | 64 |
| Year | 16.4°C | 6.8°C | 11.6°C | 696 mm | 1,831 |
Where Saint-Yon’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Fontenay-lès-B., 5.8 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, Orly, 23 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 Saint-Yon’s climate
How warm does Saint-Yon get in summer?
July is the warmest month, with average highs of 26.1°C. About 60 days a year reach 25°C, fewer than 50% of mainland French towns, and about 16 reach 30°C.
How cold does Saint-Yon get in winter?
February nights average 1.2°C. The air drops to 0°C or below on about 53 nights a year, and about 4 days a year stay below freezing all day.
How much rain does Saint-Yon get?
About 696 mm a year, less than 69% of mainland French towns. December is the wettest month (71 mm) and April the driest (48 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Orly (23 km away), averages 1,831 hours of sunshine a year.
Are these figures for Saint-Yon itself?
No: they are the normals of the Météo-France station matched to Saint-Yon, Fontenay-lès-B., 5.8 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 FONTENAY-LES-B., edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Saint-Yon →
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.