Altdorf Weather in September
What's the weather like in Altdorf (Uri) in September 2025?
The climate in Altdorf during September can be summarized as mild and damp.
September is in the fall / autumn in Altdorf and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 16°C (60°F), whilst at night 8°C (47°F) is normal.
| Daytime temperature | 15.6°C 60.1°F |
|---|---|
| Nightly temperature | 8.2°C 46.8°F |
| Average temperature | 11.9°C 53.4°F |
| Daily sunshine | 6 hrs |
| Avg rainfall | 119 mm 4.7 ins |
| Rainy days | 14 days |
| Sea temperature | 21.4°C 70.6°F |
| Humidity | 79% |
| Windspeed | 7.6kph 5 mph |
On average September is the 5th wettest month of the year in Altdorf with around 119mm 4.7 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 Altdorf
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 Altdorf in September 2025.
Other monthly averages
Best places to visit in September
Altdorf weather stats
| Hottest month: | July | 19.3°C 66.7°F |
|---|---|---|
| Driest month: | February | 74mm 2.9ins |
| Sunniest month: | July | 7.4hrs |
| Coldest month: | January | 0.6°C 33.1°F |
| Wettest month: | August | 165mm 6.5ins |
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