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United States weather

Weather in Rapid City, South Dakota for September 2026

Your guide to Rapid City weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Rapid City at the beginning of September is 27.4 °C. As the month progressed, temperatures tended to moderately rise, reaching an average of 29.1 °C by the end of September.

    • Rain 🌧️

  • Rapid City experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 116.4 mm.

    • More

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Average dry days
23
Dry days
Average rainy days
7
Rainy days
Average snowy days
0
Snow days
Average temperatures
27°/15°
Temperatures
Average wind speed
25 km/h
Avg max wind
Average humidity
45 %
Avg humidity

Rapid City Weather September

Move between months or click on a day
August
October
Mon.Tue.Wed.Thu.Fri.Sat.Sun.
1
Sunny
29°
2
Sunny
33°
3
Overcast
29°
4
Heavy rain at times
27°
5
Partly cloudy
23°
6
Sunny
23°
7
Sunny
28°
8
Sunny
31°
9
Cloudy
32°
10
Partly cloudy
32°
11
Partly cloudy
32°
12
Moderate or heavy rain shower
31°
13
Moderate rain at times
24°
14
Overcast
24°
15
Partly cloudy
30°
16
Partly cloudy
27°
17
Cloudy
23°
18
Sunny
22°
19
Sunny
23°
20
Sunny
27°
21
Sunny
23°
22
Sunny
23°
23
Overcast
22°
24
Sunny
26°
25
Sunny
29°
26
Sunny
32°
27
Sunny
26°
28
Sunny
31°
29
Sunny
33°
30
Sunny
27°

Temperatures trend during September in Rapid City

See the weather trend as well as the moving average line

September weather in Rapid City day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
Sept. 1 Sunny
Sunny
 29° /15° 0 mm 7
Sept. 2 Sunny
Sunny
 33° /18° 0 mm 9
Sept. 3 Overcast
Overcast
 29° /17° 0 mm 7
Sept. 4 Heavy rain at times
Heavy rain at times
 27° /16° 0.6 mm 7
Sept. 5 Partly cloudy
Partly cloudy
 23° /11° 0 mm 7
Sept. 6 Sunny
Sunny
 23° /9° 0 mm 6
Sept. 7 Sunny
Sunny
 28° /11° 0 mm 7
Sept. 8 Sunny
Sunny
 31° /17° 0 mm 7
Sept. 9 Cloudy
Cloudy
 32° /18° 2.2 mm 7
Sept. 10 Partly cloudy
Partly cloudy
 32° /17° 0 mm 8
Sept. 11 Partly cloudy
Partly cloudy
 32° /17° 0 mm 8
Sept. 12 Moderate or heavy rain shower
Moderate or heavy rain shower
 31° /18° 1.8 mm 7
Sept. 13 Moderate rain at times
Moderate rain at times
 24° /15° 6.4 mm 6
Sept. 14 Overcast
Overcast
 24° /13° 17.8 mm 5
Sept. 15 Partly cloudy
Partly cloudy
 30° /14° 0 mm 8
Sept. 16 Partly cloudy
Partly cloudy
 27° /15° 0.1 mm 7
Sept. 17 Cloudy
Cloudy
 23° /16° 40.7 mm 6
Sept. 18 Sunny
Sunny
 22° /13° 44.6 mm 6
Sept. 19 Sunny
Sunny
 23° /12° 0.5 mm 6
Sept. 20 Sunny
Sunny
 27° /12° 0 mm 7
Sept. 21 Sunny
Sunny
 23° /12° 1.4 mm 6
Sept. 22 Sunny
Sunny
 23° /11° 0.4 mm 7
Sept. 23 Overcast
Overcast
 22° /10° 0 mm 5
Sept. 24 Sunny
Sunny
 26° /12° 0 mm 7
Sept. 25 Sunny
Sunny
 29° /14° 0 mm 8
Sept. 26 Sunny
Sunny
 32° /18° 0 mm 8
Sept. 27 Sunny
Sunny
 26° /13° 0 mm 7
Sept. 28 Sunny
Sunny
 31° /16° 0 mm 8
Sept. 29 Sunny
Sunny
 33° /20° 0 mm 9
Sept. 30 Sunny
Sunny
 27° /13° 0 mm 7
Next
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 27° and lows near 15°, suitable for diverse activities and preferences.

How much rainfall should be expected in Rapid City during September?

Significant rainfall exceeding 116.4 mm is expected in Rapid City during September, occurring over more than 7 days. Preparing for wet conditions is recommended in your planning.

What are the typical wind conditions in Rapid City during September?

The average wind speed in Rapid City during September is 25 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 💧
Typically, Rapid City has 7 rainy days in September with a total of 116.4 mm of rainfall.

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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Location coordinates Where is Rapid City?

Get accurate weather forecasts for Rapid City, located at latitude 44.081 and longitude -103.231. Stay updated with localized weather information tailored for Rapid City.

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