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The temperatures in Delemont in September are quite cold with temperatures between 9°C and 20°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Delemont 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 Delemont in September 2026.
If you’re planning to visit Delemont in the near future, we highly recommend that you review the 14 day weather forecast for Delemont before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 3° / -4° | 9 | 10 | 12 | 134 mm | Awful | Delemont in January |
| February | 4° / -3° | 10 | 9 | 11 | 113 mm | Awful | Delemont in February |
| March | 9° / 0° | 7 | 17 | 6 | 104 mm | Awful | Delemont in March |
| April | 14° / 3° | 8 | 20 | 2 | 110 mm | Bad | Delemont in April |
| May | 18° / 6° | 11 | 20 | 0 | 189 mm | Ok | Delemont in May |
| June | 22° / 10° | 10 | 20 | 0 | 182 mm | Ok | Delemont in June |
| July | 24° / 12° | 9 | 22 | 0 | 168 mm | Good | Delemont in July |
| August | 24° / 12° | 9 | 22 | 0 | 160 mm | Good | Delemont in August |
| September | 20° / 9° | 6 | 24 | 0 | 110 mm | Good | Delemont in September |
| October | 15° / 5° | 6 | 25 | 0 | 121 mm | Good | Delemont in October |
| November | 9° / 2° | 8 | 18 | 4 | 128 mm | Awful | Delemont in November |
| December | 4° / -2° | 11 | 12 | 9 | 171 mm | Awful | Delemont in December |