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The weather in Sion in May is very cold with temperatures between -1°C and 10°C, warm clothes are a must.
There’s going to be many days of rain during the month of May in Sion.
Sion should expect an average of 15 to 22 days of rain, so be sure to bring along a waterproof jacket to stay dry this month!
You can expect a few days of snow in Sion during May. It’s important to get out your snow boots and warm mittens to stay warm while you explore Sion.
Our weather forecast can give you a great sense of what weather to expect in Sion in May 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.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -1° / -14° | 5 | 6 | 21 | 206 mm | Awful | Sion in January |
| February | 0° / -13° | 5 | 5 | 20 | 149 mm | Awful | Sion in February |
| March | 2° / -10° | 8 | 5 | 20 | 166 mm | Awful | Sion in March |
| April | 6° / -5° | 12 | 7 | 12 | 158 mm | Awful | Sion in April |
| May | 10° / -1° | 20 | 5 | 7 | 298 mm | Awful | Sion in May |
| June | 16° / 2° | 18 | 11 | 1 | 241 mm | Ok | Sion in June |
| July | 18° / 4° | 16 | 15 | 0 | 230 mm | Ok | Sion in July |
| August | 18° / 4° | 14 | 17 | 0 | 207 mm | Ok | Sion in August |
| September | 15° / 2° | 11 | 17 | 2 | 132 mm | Bad | Sion in September |
| October | 10° / -2° | 8 | 18 | 6 | 115 mm | Awful | Sion in October |
| November | 4° / -7° | 7 | 10 | 13 | 157 mm | Awful | Sion in November |
| December | -1° / -12° | 7 | 7 | 18 | 190 mm | Awful | Sion in December |