Click on a day for an hourly weather forecast
The temperatures in Altdorf in September are usually low and can range between 10°C and 19°C.
You can expect about 3 to 8 days of rain in Altdorf during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Altdorf in September 2026.
If you’re planning to visit Altdorf in the near future, we highly recommend that you review the 14 day weather forecast for Altdorf before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -3° | 7 | 9 | 15 | 111 mm | Awful | Altdorf in January |
| February | 4° / -2° | 6 | 10 | 12 | 81 mm | Awful | Altdorf in February |
| March | 9° / 1° | 6 | 18 | 7 | 76 mm | Bad | Altdorf in March |
| April | 14° / 4° | 5 | 22 | 3 | 59 mm | Ok | Altdorf in April |
| May | 17° / 8° | 11 | 20 | 0 | 157 mm | Ok | Altdorf in May |
| June | 22° / 12° | 9 | 21 | 0 | 187 mm | Ok | Altdorf in June |
| July | 23° / 13° | 9 | 22 | 0 | 174 mm | Good | Altdorf in July |
| August | 24° / 13° | 8 | 23 | 0 | 155 mm | Good | Altdorf in August |
| September | 19° / 10° | 6 | 24 | 0 | 97 mm | Good | Altdorf in September |
| October | 14° / 6° | 6 | 25 | 1 | 79 mm | Good | Altdorf in October |
| November | 9° / 2° | 5 | 21 | 4 | 53 mm | Bad | Altdorf in November |
| December | 4° / -1° | 9 | 12 | 11 | 93 mm | Awful | Altdorf in December |