South Dakota (Rapid City)
September
Weather in South Dakota for September 2026
Your guide to South Dakota weather in September - trends and predictions
Until now, September 2026 in South Dakota is slightly cooler than the historical average by 0.9 °F.
The forecast for the next days in South Dakota predicts a temperature of 19.1 °F, which is cooler than the historical average.
In general, the average temperature in South Dakota at the beginning of September is 29.6 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 26 °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 116.4 mm.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
23
Dry days
7
Rainy days
0
Snow days
27°/15°
Temperatures
25 km/h
Avg max wind
45 %
Avg humidity
South Dakota Weather September
Move between months or click on a day
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
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 28° /15° | 1.3 mm | 5 | |
| Sept. 2 | Sunny | 33° /16° | 0 mm | 8 | |
| Sept. 3 |  Overcast | 32° /18° | 0 mm | 7 | |
| Sept. 4 |  Heavy rain at times | 30° /16° | 0.5 mm | 6 | |
| Sept. 5 | Sunny | 27° /14° | 0.1 mm | 7 | |
| Sept. 6 | Sunny | 27° /12° | 0 mm | 6 | |
| Sept. 7 | Sunny | 30° /13° | 3.2 mm | 6 | |
| Sept. 8 | Sunny | 30° /16° | 0 mm | 7 | |
| Sept. 9 |  Cloudy | 31° /16° | 1.4 mm | 7 | |
| Sept. 10 | Sunny | 33° /16° | 0 mm | 8 | |
| Sept. 11 |  Partly cloudy | 31° /17° | 0 mm | 7 | |
| Sept. 12 |  Moderate or heavy rain shower | 28° /15° | 1.3 mm | 6 | |
| Sept. 13 | Moderate rain at times | 24° /13° | 5.1 mm | 6 | |
| Sept. 14 | Overcast | 25° /13° | 12.1 mm | 5 | |
| Sept. 15 | Partly cloudy | 27° /12° | 0 mm | 7 | |
| Sept. 16 | Partly cloudy | 28° /14° | 0 mm | 5 | |
| Sept. 17 | Moderate or heavy rain shower | 22° /14° | 31.4 mm | 4 | |
| Sept. 18 | Sunny | 23° /13° | 30.6 mm | 5 | |
| Sept. 19 | Sunny | 22° /13° | 1.6 mm | 4 | |
| Sept. 20 | Sunny | 23° /12° | 7.3 mm | 5 | |
| Sept. 21 | Sunny | 20° /11° | 2.1 mm | 4 | |
| Sept. 22 | Sunny | 22° /11° | 0.3 mm | 6 | |
| Sept. 23 | Overcast | 23° /11° | 0.2 mm | 4 | |
| Sept. 24 | Sunny | 25° /13° | 0 mm | 6 | |
| Sept. 25 | Sunny | 27° /13° | 0 mm | 6 | |
| Sept. 26 | Sunny | 29° /16° | 0 mm | 7 | |
| Sept. 27 | Sunny | 24° /13° | 0.1 mm | 5 | |
| Sept. 28 | Sunny | 29° /15° | 0.4 mm | 5 | |
| Sept. 29 | Sunny | 25° /16° | 0.1 mm | 5.1 | |
| Sept. 30 | Sunny | 23° /14° | 0 mm | 5.2 | |
| Next | |||||
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.
Change Month
South Dakota in September - FAQ
What are the expected maximum and minimum temperatures in South Dakota during September?
During September, expect a variety of temperatures with highs around 27° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in South Dakota during September?
Significant rainfall exceeding 116.4 mm is expected in South Dakota during September, occurring over more than 7 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in South Dakota during September?
The average wind speed in South Dakota during September is 25 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 💧
Typically, South Dakota has 7 rainy days in September with a total of 116.4 mm of rainfall.
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
Select a county for an accurate weather forecast
Top locations in South Dakota
Select a location for an accurate weather forecast
More Locations Quick links
More South Dakota weather pages
You are here
Where is South Dakota?Get accurate weather forecasts for South Dakota, located at latitude 44.081 and longitude -103.231. Stay updated with localized weather information tailored for South Dakota.
Found a mistake?
We appreciate your attention to details. Tell us here.