Interlaken Weather in September
What's the weather like in Interlaken (Bern) in September 2025?
The climate in Interlaken during September can be summarized as mild and damp.
September is in the fall / autumn in Interlaken and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 15°C (59°F), whilst at night 7°C (45°F) is normal.
| Daytime temperature | 14.8°C 58.6°F |
|---|---|
| Nightly temperature | 7.3°C 45.1°F |
| Average temperature | 11°C 51.8°F |
| Daily sunshine | 6 hrs |
| Avg rainfall | 108 mm 4.3 ins |
| Rainy days | 14 days |
| Sea temperature | 21.1°C 70.1°F |
| Humidity | 78% |
| Windspeed | 8.6kph 5 mph |
On average September is the 5th wettest month of the year in Interlaken with around 108mm 4.3 inches of rain making it a damp time to visit. This rainfall is typically spread over 14 days, although this may vary considerably.
On the flip side this corresponds to an average of 6 hours of sunshine per day.
September temperatures in Interlaken
September rainfall
September hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Interlaken in September 2025.
Other monthly averages
Best places to visit in September
Interlaken weather stats
| Hottest month: | July | 18.3°C 64.9°F |
|---|---|---|
| Driest month: | February | 80mm 3.1ins |
| Sunniest month: | July | 7.5hrs |
| Coldest month: | January | -0.3°C 31.5°F |
| Wettest month: | August | 153mm 6ins |
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