Click on a day for an hourly weather forecast
The temperatures in Thun in September are quite cold with temperatures between 5°C and 17°C, warm clothes are a must.
You can expect rain for roughly half of the month of September in Thun. 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 Thun in September 2025.
If you’re planning to visit Thun in the near future, we highly recommend that you review the 14 day weather forecast for Thun before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -8° | 9 | 9 | 13 | 184 mm | Awful | Thun in January |
| February | 3° / -6° | 9 | 8 | 13 | 133 mm | Awful | Thun in February |
| March | 7° / -4° | 9 | 14 | 8 | 146 mm | Awful | Thun in March |
| April | 11° / 0° | 11 | 17 | 3 | 153 mm | Awful | Thun in April |
| May | 14° / 3° | 16 | 15 | 0 | 272 mm | Ok | Thun in May |
| June | 18° / 6° | 16 | 14 | 0 | 253 mm | Ok | Thun in June |
| July | 20° / 8° | 14 | 17 | 0 | 246 mm | Ok | Thun in July |
| August | 21° / 7° | 12 | 19 | 0 | 220 mm | Ok | Thun in August |
| September | 17° / 5° | 8 | 22 | 0 | 131 mm | Ok | Thun in September |
| October | 12° / 1° | 7 | 24 | 1 | 146 mm | Bad | Thun in October |
| November | 7° / -3° | 8 | 17 | 5 | 164 mm | Awful | Thun in November |
| December | 3° / -7° | 9 | 12 | 11 | 190 mm | Awful | Thun in December |