Click on a day for an hourly weather forecast
The temperatures in Winterthur in September are quite cold with temperatures between 9°C and 21°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Winterthur 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 Winterthur in September 2025.
If you’re planning to visit Winterthur in the near future, we highly recommend that you review the 14 day weather forecast for Winterthur before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 4° / -4° | 7 | 11 | 13 | 141 mm | Awful | Winterthur in January |
| February | 5° / -3° | 8 | 10 | 12 | 110 mm | Awful | Winterthur in February |
| March | 10° / 0° | 7 | 16 | 7 | 102 mm | Awful | Winterthur in March |
| April | 16° / 3° | 6 | 22 | 2 | 91 mm | Ok | Winterthur in April |
| May | 19° / 6° | 9 | 22 | 0 | 166 mm | Ok | Winterthur in May |
| June | 23° / 10° | 9 | 21 | 0 | 168 mm | Good | Winterthur in June |
| July | 25° / 12° | 8 | 23 | 0 | 156 mm | Good | Winterthur in July |
| August | 25° / 12° | 6 | 25 | 0 | 121 mm | Perfect | Winterthur in August |
| September | 21° / 9° | 4 | 26 | 0 | 79 mm | Good | Winterthur in September |
| October | 15° / 5° | 6 | 25 | 0 | 91 mm | Good | Winterthur in October |
| November | 9° / 1° | 7 | 19 | 5 | 104 mm | Awful | Winterthur in November |
| December | 5° / -2° | 9 | 13 | 10 | 153 mm | Awful | Winterthur in December |