Click on a day for an hourly weather forecast
The temperatures in St. Gallen in September are quite cold with temperatures between 7°C and 19°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in St. Gallen 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 St. Gallen in September 2025.
If you’re planning to visit St. Gallen in the near future, we highly recommend that you review the 14 day weather forecast for St. Gallen before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -6° | 7 | 8 | 17 | 127 mm | Awful | St. Gallen in January |
| February | 3° / -6° | 5 | 8 | 16 | 88 mm | Awful | St. Gallen in February |
| March | 7° / -3° | 7 | 13 | 11 | 97 mm | Awful | St. Gallen in March |
| April | 12° / 1° | 7 | 18 | 5 | 84 mm | Awful | St. Gallen in April |
| May | 16° / 5° | 12 | 18 | 1 | 169 mm | Ok | St. Gallen in May |
| June | 20° / 8° | 12 | 18 | 0 | 191 mm | Ok | St. Gallen in June |
| July | 22° / 10° | 11 | 20 | 0 | 160 mm | Ok | St. Gallen in July |
| August | 22° / 10° | 10 | 21 | 0 | 172 mm | Ok | St. Gallen in August |
| September | 19° / 7° | 6 | 24 | 0 | 111 mm | Good | St. Gallen in September |
| October | 14° / 3° | 6 | 23 | 3 | 104 mm | Ok | St. Gallen in October |
| November | 8° / 0° | 5 | 17 | 8 | 85 mm | Bad | St. Gallen in November |
| December | 3° / -4° | 7 | 10 | 14 | 115 mm | Awful | St. Gallen in December |