About Sion
Sion is a Swiss municipality located in the canton of Valais (VS), at 46.230° latitude and 7.356° longitude. The municipality is part of the Valais Alps, dry continental climate, among the sunniest in Switzerland. Also known as Sion, Sion benefits from precise weather monitoring with hourly and 15-day forecasts.
Climate of Sion
The climate in Sion is characteristic of the Valais Alps, dry continental climate, among the sunniest in Switzerland. Temperatures, precipitation and wind conditions vary throughout the year with local features linked to altitude and surrounding terrain. Our data comes from official weather stations and real-time Netatmo sensors for Sion and neighboring municipalities.
On this page you will find the detailed weather forecast for Sion: current temperature, 48-hour hourly forecast, 15-day forecast, air quality, UV index, wind, precipitation and weather alerts. Updated hourly.
Climate of Sion: 1991–2020 normals
In Sion (509 m), the mean annual temperature is 10.7 °C. The warmest month is July (20.5 °C on average) and the coldest January (0.6 °C). About 592 mm of precipitation falls per year, peaking in December (69 mm) with a minimum in April (34 mm). The sun shines for about 2137 hours a year, mostly in July (269 h). On average there are 90 frost days and 21 hot days (≥ 30 °C) per year. The mean monthly maximum reaches 33.5 °C and the absolute minimum −8.9 °C.
Mean monthly precipitation (mm) — bar height relative to the wettest month.
| Month | Mean T | Abs. max | Abs. min | Precip. (mm) | Sunshine (h) | Frost days | Summer days |
|---|---|---|---|---|---|---|---|
| Jan | 0.6 °C | 11.4 °C | −8.9 °C | 53 | 90 | 24 | 0 |
| Feb | 2.3 °C | 15.1 °C | −7.5 °C | 42 | 130 | 20 | 0 |
| Mar | 7.1 °C | 20.8 °C | −3.7 °C | 38 | 188 | 9 | 0 |
| Apr | 11.1 °C | 24.7 °C | −0.4 °C | 34 | 209 | 1 | 2 |
| May | 15.1 °C | 29.0 °C | 3.6 °C | 53 | 225 | 0 | 8 |
| Jun | 18.8 °C | 32.4 °C | 7.2 °C | 49 | 251 | 0 | 17 |
| Jul | 20.5 °C | 33.5 °C | 9.5 °C | 62 | 269 | 0 | 22 |
| Aug | 19.8 °C | 32.9 °C | 8.6 °C | 60 | 248 | 0 | 20 |
| Sep | 15.7 °C | 27.7 °C | 5.2 °C | 38 | 208 | 0 | 7 |
| Oct | 10.8 °C | 23.2 °C | 0.2 °C | 43 | 159 | 2 | 0 |
| Nov | 5.1 °C | 18.0 °C | −4.9 °C | 51 | 94 | 11 | 0 |
| Dec | 1.1 °C | 11.9 °C | −8.4 °C | 69 | 66 | 23 | 0 |
| Year | 10.7 °C | 33.5 °C | −8.9 °C | 592 | 2137 | 90 | 77 |
Source: MeteoSwiss open data (1991–2020 normals) — stations Sion (2 km, 482 m), Montana (11 km, 1423 m), Les Diablerets (16 km, 2964 m), adjusted to the elevation of Sion (509 m) using a 0.55 °C/100 m lapse rate. Indicative, rounded values.
Nearby cities
Check the weather of cities near Sion:
- Weather Savièse
- Weather Grimisuat
- Weather Veysonnaz
- Weather Vex
- Weather Nendaz
- Weather Ayent
- Weather Saint-Léonard
- Weather Vétroz
- Weather Mont-Noble
- Weather Conthey
- Weather Hérémence
- Weather Arbaz
→ Nearby cities · Canton Valais
Frequently asked questions about weather in Sion
What is the weather in Sion today?
At the top of the page you will find the current temperature, precipitation and wind in Sion, updated in real time.
What is the 15-day forecast for Sion?
The "15-day forecast" section shows min/max temperatures, precipitation and wind expected for the next 15 days in Sion.
Will it rain tomorrow in Sion?
Check the 48-hour hourly forecast to see exactly when precipitation is expected in Sion.
What is the air quality in Sion?
The air quality section displays the AQI index and PM2.5, PM10 and ozone concentrations measured near Sion.
Are there weather alerts for Sion?
Weather alerts (storms, high winds, extreme temperatures) are shown as a banner at the top of the page when active.
At what altitude is Sion located?
Sion sits at around 509 m above sea level in the canton of Valais. This elevation directly affects the temperatures, rain-snow line and snow cover shown in the forecasts.
What is the warmest month in Sion?
The warmest month in Sion is July, averaging 20.5 °C (1991–2020 normal). The coldest is January at 0.6 °C.
How much does it rain in Sion per year?
Sion receives about 592 mm of precipitation a year. The wettest month is December (69 mm), the driest April (34 mm).
When is the best time to visit Sion?
For warmth and sunshine: July (20.5 °C on average, 269 h of sun). The coldest month is January (0.6 °C). Check the 15-day forecast above for your dates.