South Dakota (Sioux Falls)
September
Weather in South Dakota for September 2025
Your guide to South Dakota weather in September - trends and predictions
Until now, September 2025 in South Dakota has been significantly cooler than historical averages by -6.2 °F, with average temperature of 23.4 °F.
The forecast for the next days in South Dakota predicts temperatures to be around 30 °F, close to the historical average.
In general, the average temperature in South Dakota at the beginning of September is 28.7 °F. As the month progressed, temperatures tended to significantly warm up, reaching an average of 33 °F by the end of September.
South Dakota experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 41.1 mm.
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Temperatures
Rain 🌧️
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23
Dry days
7
Rainy days
0
Snow days
29°/12°
Temperatures
24 km/h
Avg max wind
54 %
Avg humidity
South Dakota Weather September
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What’s the Weather Like in South Dakota This September?
Discover the average temperatures and weather trends across South Dakota’s cities this September.
Temperatures trend during September in South Dakota
See the weather trend as well as the moving average line
September weather in South Dakota day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Partly cloudy | 28° /14° | 16 mm | 7 | |
| Sept. 2 |  Mist | 33° /13° | 0 mm | 7 | |
| Sept. 3 |  Thundery outbreaks possible | 31° /13° | 0.5 mm | 7 | |
| Sept. 4 |  Sunny | 33° /12° | 2.5 mm | 8 | |
| Sept. 5 |  Patchy rain possible | 27° /12° | 0.9 mm | 7 | |
| Sept. 6 |  Cloudy | 23° /9° | 0 mm | 5 | |
| Sept. 7 | Sunny | 26° /4° | 0.1 mm | 7 | |
| Sept. 8 | Sunny | 31° /10° | 0 mm | 7 | |
| Sept. 9 | Thundery outbreaks possible | 30° /16° | 1.3 mm | 7 | |
| Sept. 10 | Fog | 30° /16° | 0.2 mm | 6 | |
| Sept. 11 | Mist | 29° /11° | 0 mm | 7 | |
| Sept. 12 | Thundery outbreaks possible | 30° /13° | 0 mm | 7 | |
| Sept. 13 | Partly cloudy | 33° /15° | 0 mm | 8 | |
| Sept. 14 | Partly cloudy | 30° /13° | 0.3 mm | 7 | |
| Sept. 15 | Patchy rain possible | 31° /17° | 1 mm | 1.4 | |
| Sept. 16 | Patchy rain possible | 34° /16° | 0.1 mm | 1.4 | |
| Sept. 17 |  Moderate rain | 30° /16° | 6 mm | 1.1 | |
| Sept. 18 | Moderate rain | 25° /16° | 9.7 mm | 0.9 | |
| Sept. 19 | Patchy rain possible | 24° /15° | 2.7 mm | 0 | |
| Sept. 20 | Patchy rain possible | 22° /14° | 2.1 mm | 4 | |
| Sept. 21 | Fog | 27° /14° | 0 mm | 4 | |
| Sept. 22 | Sunny | 31° /16° | 0 mm | 6 | |
| Sept. 23 | Sunny | 30° /15° | 0 mm | 6 | |
| Sept. 24 | Sunny | 35° /20° | 0 mm | 7 | |
| Sept. 25 | Patchy rain possible | 35° /23° | 0.2 mm | 6 | |
| Sept. 26 | Sunny | 34° /19° | 0 mm | 7 | |
| Sept. 27 | Sunny | 34° /22° | 0 mm | 7 | |
| Sept. 28 | Sunny | 33° /20° | 0 mm | 7 | |
| Sept. 29 |  Patchy light drizzle | 32° /14° | 1.2 mm | 8 | |
| Sept. 30 |  Overcast | 28° /14° | 0 mm | 7 | |
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Important Notice
Our weather forecast for South Dakota in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the South Dakota forecast closer to your planned date for the most up-to-date weather information.
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South Dakota in September - FAQ
What are the expected maximum and minimum temperatures in South Dakota during September?
Enjoy moderate daytime temperatures of up to 29° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in South Dakota during September?
In September, South Dakota can expect light to moderate rainfall, totaling 41.1 mm across approximately 7 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in South Dakota during September?
The average wind speed in South Dakota during September is 24 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in South Dakota
Explore the daily rainfall trends and prepare for South Dakotas September weather 💧
UV exposure in South Dakota during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Counties in South Dakota
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