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The temperatures in Rheinfelden 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 Rheinfelden 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 Rheinfelden in September 2026.
If you’re planning to visit Rheinfelden in the near future, we highly recommend that you review the 14 day weather forecast for Rheinfelden before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 4° / -3° | 10 | 9 | 11 | 125 mm | Awful | Rheinfelden in January |
| February | 6° / -2° | 9 | 10 | 10 | 106 mm | Awful | Rheinfelden in February |
| March | 11° / 1° | 9 | 17 | 5 | 98 mm | Awful | Rheinfelden in March |
| April | 16° / 4° | 7 | 22 | 1 | 104 mm | Ok | Rheinfelden in April |
| May | 19° / 7° | 11 | 20 | 0 | 183 mm | Ok | Rheinfelden in May |
| June | 23° / 11° | 10 | 20 | 0 | 188 mm | Good | Rheinfelden in June |
| July | 25° / 13° | 8 | 23 | 0 | 179 mm | Good | Rheinfelden in July |
| August | 25° / 13° | 8 | 23 | 0 | 150 mm | Good | Rheinfelden in August |
| September | 21° / 9° | 6 | 24 | 0 | 92 mm | Good | Rheinfelden in September |
| October | 16° / 6° | 6 | 24 | 0 | 114 mm | Good | Rheinfelden in October |
| November | 10° / 2° | 8 | 19 | 3 | 126 mm | Awful | Rheinfelden in November |
| December | 6° / -1° | 11 | 12 | 8 | 157 mm | Awful | Rheinfelden in December |