Sion weather in September (Canton of Valais, Switzerland)

People don't tend to visit Sion in September since it is known as a chilly month. The average maximum daytime temperature in Sion in September lies at 10.6°C (51.08°F). The average minimum temperature goes down to around 4.7°C (40.46°F) (often the minimum temperature is noted at night).

Rainfall during September is high with an average of 168mm (6.6 inchec). There are generally around 15 rainy days.


Sion, monthly averages in September

Show in Fahrenheit
Min Temperature 4 °C  
Max Temperature 10 °C  
Chance of Rain 52%  
Precipitation 168mm  
Rainy days 16 days  
Humidity 71% *  
Sunshine 210 hrs *  
Percentage Sunshine 65% *  

Where to stay in Sion

Where to go in Switzerland in September

Find out more about the weather in Switzerland in September and which places have the best weather conditions in this month.

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Legend perfect weather pleasant tolerable unpleasant poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20-29ºC / 68-84ºF and not too much precipitation (less than 90mm / 3.5inches a month).

So what to wear in September? Visitors traveling to Sion should plan on bringing a totally waterproof coat since it will often be raining. However, also plan on bringing your warm clothes since it can be a bit chilly during this period.

What To Do

We rated the following activities from 1 (least suitable) to 10 (best) to do in September.

Outdoor sports

Interested in more climate information?

Weather and Climate provides you with all the information you need about the climate in Sion.

Our site offers climate and forecast data for every country in the world. Are you going to Switzerland? On this website you can find historical weather averages for many cities in Switzerland. Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal climate conditions. Find out where to go with our weather planner.