Hardly any mainland French towns see harsher January nights than Saint-Ismier
In July the day’s top temperature is typically 27.7°C. It is a wet place: more rain falls here than on 93% of mainland French towns. From frosty January to warm July, readings climb 30°C. Waterproofs come out on about 113 days a year, each with 1 mm of rain or more.
These are the figures of Météo-France’s Saint-Pierre-de-Soucy station, 33 km north-east; at that distance they describe the area more than the town.
A year in Saint-Ismier at a glance
Each month’s typical high and low in °C, at the Saint-Pierre-de-Soucy station.
What a year in Saint-Ismier feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Saint-Pierre-de-Soucy.
About 1,122 mm of rain a year
December is the wettest month and February the driest. About 41 days a year bring 10 mm or more. 38th wettest of 110 towns of 2,500+ in Isère.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Grenoble-Saint-Geoirs
A frosty town: 79 frosts and 82 days of 25°C a year
On about 79 nights a year the air drops to 0°C or below, and on about 6 days it stays below freezing all day. About 82 days a year reach 25°C, and 28 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Saint-Pierre-de-Soucy: 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 Saint-Pierre-de-Soucy
Saint-Pierre-de-Soucy is 33 km north-east of Saint-Ismier. Every figure on this page is the station’s, not a measurement in Saint-Ismier itself.
| Station (Météo-France number) | Saint-Pierre-de-Soucy (73276001) |
| Distance from the town | 33 km north-east |
| Station altitude | 351 m |
| Town altitude (its center) | 323 m |
| Period | 1991–2015 (the station’s own record) |
| Nearest station of any kind | 3.7 km |
| Sunshine measured at | Grenoble-Saint-Geoirs, 43 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-Ismier 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 Isère.
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-Ismier | Saint-Pierre-de-Soucy | 27.7°C | −1.8°C | 1,122 mm |
| Saint-Nazaire-les-Eymes 1.5 km | same station | 27.7°C about the same | −1.8°C about the same | 1,122 mm |
| Montbonnot-Saint-Martin 3 km | Pont-de-Beauvoisin | 28.5°C 0.8°C warmer | −1.2°C 0.6°C milder | 1,166 mm |
| Bernin 3.4 km | Pont-de-Beauvoisin | 28.5°C 0.8°C warmer | −1.2°C 0.6°C milder | 1,166 mm |
| Le Versoud 4.2 km | Pont-de-Beauvoisin | 28.5°C 0.8°C warmer | −1.2°C 0.6°C milder | 1,166 mm |
| Villard-Bonnot 4.8 km | Pont-de-Beauvoisin | 28.5°C 0.8°C warmer | −1.2°C 0.6°C milder | 1,166 mm |
| Domène 5 km | Pont-de-Beauvoisin | 28.5°C 0.8°C warmer | −1.2°C 0.6°C milder | 1,166 mm |
Saint-Ismier weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Saint-Pierre-de-Soucy station; sunshine at Grenoble-Saint-Geoirs.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 5.5°C | −1.8°C | 1.9°C | 98 mm | 91 |
| February | 7.9°C | −1.5°C | 3.2°C | 73 mm | 112 |
| March | 13.8°C | 2.1°C | 7.9°C | 85 mm | 173 |
| April | 17.6°C | 5.1°C | 11.3°C | 80 mm | 190 |
| May | 21.7°C | 9.4°C | 15.5°C | 98 mm | 221 |
| June | 25.5°C | 12.8°C | 19.2°C | 97 mm | 258 |
| July | 27.7°C | 14.6°C | 21.1°C | 95 mm | 292 |
| August | 27.2°C | 14.3°C | 20.7°C | 94 mm | 263 |
| September | 22.2°C | 10.9°C | 16.6°C | 89 mm | 199 |
| October | 16.9°C | 7.4°C | 12.2°C | 95 mm | 140 |
| November | 9.9°C | 2.3°C | 6.1°C | 107 mm | 91 |
| December | 5.5°C | −1.0°C | 2.3°C | 112 mm | 78 |
| Year | 16.8°C | 6.2°C | 11.5°C | 1,122 mm | 2,108 |
Where Saint-Ismier’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Saint-Pierre-de-Soucy, 33 km away: statistics for 1991–2020 (the station’s own years, 1991–2015, 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, Grenoble-Saint-Geoirs, 43 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 Isère.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Saint-Ismier’s climate
How warm does Saint-Ismier get in summer?
July is the warmest month, with average highs of 27.7°C. About 82 days a year reach 25°C, more than 72% of mainland French towns, and about 28 reach 30°C.
How cold does Saint-Ismier get in winter?
January nights average −1.8°C. The air drops to 0°C or below on about 79 nights a year, and about 6 days a year stay below freezing all day.
How much rain does Saint-Ismier get?
About 1,122 mm a year, more than 93% of mainland French towns. December is the wettest month (112 mm) and February the driest (73 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Grenoble-Saint-Geoirs (43 km away), averages 2,108 hours of sunshine a year.
Are these figures for Saint-Ismier itself?
No: they are the normals of the Météo-France station matched to Saint-Ismier, Saint-Pierre-de-Soucy, 33 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 ST-PIERRE DE SOUCY, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Saint-Ismier →
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.