Rapid City in September
8.2out of 10
Yes, a good time to go
Warm and comfortable: highs around 24°C. Some rain: about 7 rainy days.
24°CAvg high
9°CAvg low
7Rainy days (41 mm)
12:17 hDaylight
06:39Sunrise · 18:56 Sunset
Why this score
- Warm and comfortable: highs around 24°C
- Some rain: about 7 rainy days
What to wear and pack
- T-shirts and light layers
- A light jacket for cooler evenings
How reliable is the forecast?
Rainfall in September is fairly consistent from year to year (2.2 days). Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 3°C | -8°C | 13 mm | 4 | – | – | 4.8 |
| February | 4°C | -7°C | 20 mm | 5 | – | – | 4.8 |
| March | 9°C | -3°C | 40 mm | 8 | – | – | 5.7 |
| April | 14°C | 1°C | 80 mm | 11 | – | – | 6.1 |
| May | 19°C | 6°C | 112 mm | 14 | – | – | 6.5 |
| June | 24°C | 12°C | 97 mm | 14 | – | – | 7.1 |
| July | 29°C | 15°C | 78 mm | 14 | – | – | 7.3 |
| August | 28°C | 14°C | 61 mm | 11 | – | – | 7.6 |
| September | 24°C | 9°C | 41 mm | 7 | – | – | 8.2 |
| October | 15°C | 3°C | 50 mm | 7 | – | – | 7.0 |
| November | 8°C | -3°C | 20 mm | 4 | – | – | 5.9 |
| December | 3°C | -7°C | 15 mm | 4 | – | – | 5.0 |
Frequently asked questions
How hot is Rapid City in September?
Daytime highs average 24°C and nights about 9°C.
When is the best time to visit Rapid City?
The best months are September, August.