Thônex climate — normals and trends
Thônex (Switzerland) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 8.6 °C and it receives 1,405 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (17.8 °C on average) and the coldest is January (-0.6 °C). Rainfall peaks in May.
Thônex averages 100 frost days, 2 hot days (≥ 30 °C) and 161 rainy days per year.
Thônex has warmed by +3.0 °C between 1940 and 2025, or +0.35 °C per decade. This trend is statistically significant.
The number of frost days there went from about 130 to 70 per year over the period.
The hottest day of the period reached 36.4 °C (on 7 July 2015) and the coldest -24.2 °C (on 29 December 1941).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
ThônexCanton of Geneva
- coords
- 46.19°, 6.20°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.6°C
Average daily high
12.9°C
Average daily low
4.5°C
Annual rainfall
1,405mm
Sunshine / day
8.9h
Mean relative humidity
78%
Average peak wind
9.6km/h
Seasonal range
18.4°C
Frost days (< 0 °C)
100 d/yr
Hot days (≥ 30 °C)
2 d/yr
Rainy days (≥ 1 mm)
161 d/yr
Annual snowfall
147.3 cm
Average feels-like high
11.3 °C
Average feels-like low
2.3 °C
Average peak gust
30.8 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
13.0 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+3.0 °C
since 1940
+0.4 °C per decade · r² = 0.71 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
36.4 °C
7 July 2015
Coldest day
-24.2 °C
29 December 1941
Wettest day
68 mm
31 July 1977
Windiest day
34.9 km/h
25 April 1972
Strongest gust
122.8 km/h
26 December 1999
Hottest feels-like
38.0 °C
26 June 2019
Coldest feels-like
-28.8 °C
29 December 1941
Snowiest day
32.2 cm
17 April 2005
Sunniest day
15.0 h
20 May 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 6.1 °C | +3.1 °C | 187 mm | +74 mm |
| Feb | 7.6 °C | +2.9 °C | 53 mm | -52 mm |
| Mar | 11.6 °C | +2.9 °C | 59 mm | -49 mm |
| Apr | 16.3 °C | +3.7 °C | 103 mm | -8 mm |
| May | 18.0 °C | +1.3 °C | 125 mm | -14 mm |
| Jun | 26.3 °C | +6.1 °C | 132 mm | +2 mm |
| Jul | 24.2 °C | +1.7 °C | 106 mm | -11 mm |
| Aug | 26.4 °C | +4.4 °C | 86 mm | -39 mm |
| Sep | 18.7 °C | +0.1 °C | 204 mm | +96 mm |
| Oct | 13.6 °C | -0.3 °C | 190 mm | +84 mm |
| Nov | 8.9 °C | +1.2 °C | 144 mm | +21 mm |
| Dec | 6.6 °C | +2.7 °C | 31 mm | -91 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Thônex?
Thônex has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 8.6 °C and it receives 1,405 mm of precipitation per year.
What is the hottest day ever recorded in Thônex?
The hottest day measured in Thônex between 1940 and 2025 was 7 July 2015, reaching 36.4 °C.
What is the coldest day in Thônex?
The coldest day measured in Thônex between 1940 and 2025 was 29 December 1941, at -24.2 °C.
Does it snow in Thônex?
Yes. Thônex gets on average 147.3 cm of snow per year and has around 100 frost days.
Has the climate of Thônex warmed?
Yes: Thônex warmed by +3.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Thônex?
The wettest day measured in Thônex between 1940 and 2025 was 31 July 1977, with 68 mm of rain in 24 hours.
What was the windiest day in Thônex?
The windiest day measured in Thônex between 1940 and 2025 was 25 April 1972, with winds reaching 34.9 km/h.
What is the warmest month in Thônex?
The warmest month in Thônex is July (17.8 °C on average); the coldest is January (-0.6 °C).
How much does it rain in Thônex?
Thônex receives on average 1,405 mm of precipitation per year, spread over about 161 rainy days.
Is it sunny in Thônex?
Thônex gets on average 8.9 hours of sunshine per day, roughly 3,249 hours per year over 1940-2025.
What is the biggest single-day snowfall in Thônex?
The heaviest 24-hour snowfall measured in Thônex between 1940 and 2025 was 17 April 2005, with 32.2 cm.
Are there tropical nights in Thônex?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Thônex.
What was the most extreme apparent temperature in Thônex?
In Thônex, between 1940 and 2025, the highest apparent temperature reached 38.0 °C on 26 June 2019, and the lowest was -28.8 °C on 29 December 1941.
Compare Thônex with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Thônex