Click on a day for an hourly weather forecast
The temperatures in Sioux Falls in September are comfortable with low of 12°C and and high up to 24°C.
You can expect about 3 to 8 days of rain in Sioux Falls 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 Sioux Falls in September 2025.
If you’re planning to visit Sioux Falls in the near future, we highly recommend that you review the 14 day weather forecast for Sioux Falls before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -5° / -13° | 2 | 15 | 13 | 35 mm | Awful | Sioux Falls in January |
| February | -4° / -12° | 2 | 15 | 11 | 39 mm | Awful | Sioux Falls in February |
| March | 6° / -2° | 5 | 17 | 9 | 67 mm | Awful | Sioux Falls in March |
| April | 13° / 3° | 6 | 20 | 4 | 110 mm | Bad | Sioux Falls in April |
| May | 20° / 10° | 9 | 22 | 0 | 135 mm | Ok | Sioux Falls in May |
| June | 25° / 16° | 8 | 22 | 0 | 185 mm | Good | Sioux Falls in June |
| July | 28° / 17° | 6 | 25 | 0 | 109 mm | Perfect | Sioux Falls in July |
| August | 28° / 15° | 6 | 25 | 0 | 118 mm | Perfect | Sioux Falls in August |
| September | 24° / 12° | 5 | 25 | 0 | 94 mm | Perfect | Sioux Falls in September |
| October | 14° / 5° | 4 | 25 | 2 | 83 mm | Ok | Sioux Falls in October |
| November | 7° / -1° | 2 | 23 | 5 | 33 mm | Bad | Sioux Falls in November |
| December | -2° / -9° | 3 | 16 | 12 | 43 mm | Awful | Sioux Falls in December |