The weather in Sion in August is very cold with temperatures between 4°C and 18°C, warm clothes are a must.
You can expect rain for roughly half of the month of August in Sion. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Sion in August 2025.
If you’re planning to visit Sion in the near future, we highly recommend that you review the 14 day weather forecast for Sion before you arrive.
Temperatures
18° / 4°
Rainy Days
14
Snowy Days
0
Dry Days
17
Rainfall
207
mm
Sun Hours
10.8
Hrs
