Sion Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Sion.
Climate overview of Sion
Temperatures in Sion, Canton of Valais, Switzerland, vary greatly throughout the year. July is the hottest month at 19°C (66°F), while January is the coldest at -3°C (27°F).
The city receives considerable rain/snowfall, with around 1636 mm (64 in) annually. June is the wettest month. July is the sunniest month, averaging 9.0 hours of sunshine per day.
Sion Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Sion — and find the best time to visit.
Monthly Temperature in Sion
The climate in Sion is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a pleasant 19°C (66°F) in July to a very cold -3°C (27°F) in the coolest month, January.
Nights vary from 8°C (46°F) in July to around -13°C (9°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Sion
Sion has a notably wet climate with abundant precipitation, recording 1636 mm (64 in) of rain/snowfall per year. Precipitation levels in Sion remain relatively steady throughout the year. June has the most rain, with 167 mm (6.6 in) over 18 days. In the driest month October, this drops slightly to 113 mm (4.4 in), making the city's climate fairly predictable. For more details, please visit our Sion Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Sion
For those who appreciate different seasons, Sion serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 9.0 hours of sunshine daily, and embrace the darker days in December, offering only 2.3 hours of daily sunlight.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Humidity in Sion by Month
The relative humidity is high throughout the year in Sion.
The city experiences its highest humidity in December, reaching 83%. In April, the humidity drops to its lowest level at 59%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Wind Speed in Sion
The mean wind speed varies between 1 m/s (2 knots) and 2 m/s (4 knots) throughout the year. It is lowest in January, October, November and December and highest during February, March, April, May, June, July, August and September. What does this mean?
The mean monthly wind speed over the year (meters per second)
Best Time to Visit Sion
The wettest months are May, June and July, when precipitation is at its highest. Wondering where to travel based on your weather preferences? Our recommendation tool helps you find destinations with your ideal climate conditions. Use our weather planner to find your perfect destination.
Frequently asked questions about the climate in Sion
What is the best time to visit Sion?
July and August typically offer the most optimal weather in Sion. In contrast, January, February, March, April, May, October, November and December tend to have less optimal conditions.
What temperatures can I expect in Sion?
Daytime highs range from -3°C (27°F) in January to 19°C (66°F) in July. Nighttime lows range from -13°C (9°F) to 8°C (46°F). Temperatures vary considerably through the year.
How much rain does Sion get?
Annual rainfall is around 1636 mm (64 in). June is the wettest month with 167 mm (6.6 in), while October is the driest with 113 mm (4.4 in).
How sunny is Sion?
Sion receives around 2,171 hours of sunshine per year. July is the sunniest month with 270 hours, while December is the cloudiest with just 70 hours. Overall, Sion enjoys abundant sunshine.
Sion 3-Day Forecast
Sion 3-Day Forecast
Sion on the map
Sion is highlighted — select any city to see its climate.
Popular this month
Where to go in July — average daytime high across popular destinations.
Zürich
25°C (77°F) Crans-Montana
19°C (66°F) Engelberg19°C (66°F) Nendaz19°C (66°F) Saas-Fee17°C (63°F) Davos17°C (63°F) Grindelwald17°C (63°F) Zermatt15°C (59°F) 
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