Few mainland French towns have colder winter nights than Sonnaz
The warmest part of a July day comes in at 28.1°C on average. Only 30°C separates winter nights from summer afternoons. Rain is plentiful here, more than falls on 94% of mainland French towns. Warm coats and heating bills mark the months from November to March, when means dip under 10°C.
These are the figures of Météo-France’s Challes-les-Eaux station, 7.3 km south-east.
A year in Sonnaz at a glance
Each month’s typical high and low in °C, at the Challes-les-Eaux station.
What a year in Sonnaz feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Challes-les-Eaux.
About 1,148 mm of rain a year
December is the wettest month and February the driest. About 42 days a year bring 10 mm or more. 15th wettest of 37 towns of 2,500+ in Savoie.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Chambery-Aix
A frosty town: 80 frosts and 86 days of 25°C a year
On about 80 nights a year the air drops to 0°C or below, and on about 4 days it stays below freezing all day. About 86 days a year reach 25°C, and 30 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Challes-les-Eaux: 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 Challes-les-Eaux
Challes-les-Eaux is 7.3 km south-east of Sonnaz. Every figure on this page is the station’s, not a measurement in Sonnaz itself.
| Station (Météo-France number) | Challes-les-Eaux (73064001) |
| Distance from the town | 7.3 km south-east |
| Station altitude | 298 m |
| Town altitude (its center) | 348 m |
| Period | 1991–2020 |
| Nearest station of any kind | 3.9 km |
| Sunshine measured at | Chambery-Aix, 3.9 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 Sonnaz 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 Savoie.
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 |
|---|---|---|---|---|
| Sonnaz | Challes-les-Eaux | 28.1°C | −1.8°C | 1,148 mm |
| La Motte-Servolex 4.1 km | Chambery-Aix | 27.8°C about the same | −0.7°C 1.1°C milder | 1,204 mm |
| Chambéry 4.6 km | same station | 28.1°C about the same | −1.8°C about the same | 1,148 mm |
| Drumettaz-Clarafond 4.9 km | Chambery-Aix | 27.8°C about the same | −0.7°C 1.1°C milder | 1,204 mm |
| Bassens 4.9 km | same station | 28.1°C about the same | −1.8°C about the same | 1,148 mm |
| Saint-Alban-Leysse 5.4 km | same station | 28.1°C about the same | −1.8°C about the same | 1,148 mm |
| Le Bourget-du-Lac 5.7 km | Chambery-Aix | 27.8°C about the same | −0.7°C 1.1°C milder | 1,204 mm |
Sonnaz weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Challes-les-Eaux station; sunshine at Chambery-Aix.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 6.4°C | −1.8°C | 2.3°C | 95 mm | 77 |
| February | 8.7°C | −1.5°C | 3.6°C | 74 mm | 102 |
| March | 13.9°C | 1.7°C | 7.8°C | 87 mm | 158 |
| April | 17.7°C | 5.1°C | 11.4°C | 83 mm | 176 |
| May | 21.7°C | 9.5°C | 15.6°C | 100 mm | 202 |
| June | 25.6°C | 13.2°C | 19.4°C | 97 mm | 236 |
| July | 28.1°C | 15.0°C | 21.5°C | 93 mm | 262 |
| August | 27.7°C | 14.6°C | 21.1°C | 100 mm | 237 |
| September | 22.8°C | 11.0°C | 16.9°C | 97 mm | 181 |
| October | 17.4°C | 7.2°C | 12.3°C | 101 mm | 124 |
| November | 10.8°C | 2.3°C | 6.5°C | 108 mm | 75 |
| December | 6.8°C | −1.0°C | 2.9°C | 112 mm | 66 |
| Year | 17.3°C | 6.3°C | 11.8°C | 1,148 mm | 1,895 |
Where Sonnaz’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Challes-les-Eaux, 7.3 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, Chambery-Aix, 3.9 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 Savoie.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Sonnaz’s climate
How warm does Sonnaz get in summer?
July is the warmest month, with average highs of 28.1°C. About 86 days a year reach 25°C, more than 77% of mainland French towns, and about 30 reach 30°C.
How cold does Sonnaz get in winter?
January nights average −1.8°C. The air drops to 0°C or below on about 80 nights a year, and about 4 days a year stay below freezing all day.
How much rain does Sonnaz get?
About 1,148 mm a year, more than 94% of mainland French towns. December is the wettest month (112 mm) and February the driest (74 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Chambery-Aix (3.9 km away), averages 1,895 hours of sunshine a year.
Are these figures for Sonnaz itself?
No: they are the normals of the Météo-France station matched to Sonnaz, Challes-les-Eaux, 7.3 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 CHALLES LES EAUX, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Sonnaz →
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.