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The weather in Interlaken in September is very cold with temperatures between 3°C and 12°C, warm clothes are a must.
You can expect rain for roughly half of the month of September in Interlaken. 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.
You can expect a few days of snow in Interlaken during September. It’s important to get out your snow boots and warm mittens to stay warm while you explore Interlaken.
Our weather forecast can give you a great sense of what weather to expect in Interlaken in September 2025.
If you’re planning to visit Interlaken in the near future, we highly recommend that you review the 14 day weather forecast for Interlaken before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -3° / -12° | 4 | 5 | 22 | 145 mm | Awful | Interlaken in January |
| February | -2° / -12° | 3 | 5 | 21 | 111 mm | Awful | Interlaken in February |
| March | 0° / -9° | 7 | 4 | 23 | 148 mm | Awful | Interlaken in March |
| April | 4° / -5° | 9 | 4 | 20 | 170 mm | Awful | Interlaken in April |
| May | 7° / -1° | 17 | 2 | 15 | 296 mm | Awful | Interlaken in May |
| June | 13° / 3° | 19 | 7 | 4 | 306 mm | Awful | Interlaken in June |
| July | 16° / 6° | 19 | 11 | 1 | 296 mm | Ok | Interlaken in July |
| August | 16° / 6° | 17 | 13 | 1 | 288 mm | Ok | Interlaken in August |
| September | 12° / 3° | 12 | 14 | 5 | 162 mm | Awful | Interlaken in September |
| October | 7° / -2° | 7 | 13 | 11 | 149 mm | Awful | Interlaken in October |
| November | 2° / -6° | 5 | 7 | 19 | 143 mm | Awful | Interlaken in November |
| December | -2° / -11° | 4 | 7 | 21 | 130 mm | Awful | Interlaken in December |