Rapid City (SD)
September
Weather in Rapid City, South Dakota for September 2025
Your guide to Rapid City weather in September - trends and predictions
In general, the average temperature in Rapid City at the beginning of September is 29.3 °F. As the month progressed, temperatures tended to slightly increase, reaching an average of 29.7 °F by the end of September.
With an average of 5 rainy days, Rapid City experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
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25
Dry days
5
Rainy days
0
Snow days
29°/15°
Temperatures
26 km/h
Avg max wind
35 %
Avg humidity
Rapid City Weather September
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Temperatures trend during September in Rapid City
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September weather in Rapid City day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 28° /15° | 0 mm | 7 | |
| Sept. 2 | Sunny | 35° /19° | 0 mm | 9 | |
| Sept. 3 |  Overcast | 36° /20° | 0 mm | 8 | |
| Sept. 4 |  Heavy rain at times | 27° /19° | 1.3 mm | 6 | |
| Sept. 5 |  Partly cloudy | 25° /14° | 0 mm | 7 | |
| Sept. 6 | Sunny | 25° /12° | 0 mm | 6 | |
| Sept. 7 | Sunny | 29° /13° | 0 mm | 7 | |
| Sept. 8 | Sunny | 32° /14° | 0 mm | 8 | |
| Sept. 9 |  Cloudy | 34° /17° | 0 mm | 7 | |
| Sept. 10 | Partly cloudy | 34° /19° | 0 mm | 8 | |
| Sept. 11 | Partly cloudy | 33° /17° | 0 mm | 8 | |
| Sept. 12 |  Moderate or heavy rain shower | 33° /19° | 3.6 mm | 7 | |
| Sept. 13 | Moderate rain at times | 25° /14° | 0.5 mm | 6 | |
| Sept. 14 | Overcast | 29° /12° | 0 mm | 6 | |
| Sept. 15 | Partly cloudy | 30° /14° | 0 mm | 8 | |
| Sept. 16 | Partly cloudy | 31° /16° | 0.1 mm | 8 | |
| Sept. 17 | Cloudy | 31° /18° | 2.7 mm | 7 | |
| Sept. 18 | Sunny | 27° /14° | 8 mm | 7 | |
| Sept. 19 | Sunny | 26° /14° | 0 mm | 7 | |
| Sept. 20 | Sunny | 30° /13° | 0 mm | 8 | |
| Sept. 21 | Sunny | 19° /11° | 0 mm | 5 | |
| Sept. 22 | Sunny | 20° /7° | 0 mm | 6 | |
| Sept. 23 | Overcast | 23° /11° | 0 mm | 5 | |
| Sept. 24 | Sunny | 25° /12° | 0 mm | 7 | |
| Sept. 25 | Sunny | 30° /14° | 0 mm | 8 | |
| Sept. 26 | Sunny | 34° /19° | 0 mm | 8 | |
| Sept. 27 | Sunny | 28° /14° | 0 mm | 7 | |
| Sept. 28 | Sunny | 32° /18° | 0 mm | 8 | |
| Sept. 29 | Sunny | 35° /22° | 0 mm | 9 | |
| Sept. 30 | Sunny | 24° /10° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Rapid City 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 Rapid City forecast closer to your planned date for the most up-to-date weather information.
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Rapid City in September - FAQ
What are the expected maximum and minimum temperatures in Rapid City during September?
During September, expect a variety of temperatures with highs around 29° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in Rapid City during September?
Expect minimal rainfall in Rapid City during September, with a total of 16.2 mm over approximately 5 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in Rapid City during September?
The average wind speed in Rapid City during September is 26 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Rapid City
Explore the daily rainfall trends and prepare for Rapid Citys September weather 💧
UV exposure in Rapid City during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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