September weather in Rapid City, SD
The average temperature in Rapid City in September is 62.4°F (50.8°F–74.0°F). Average precipitation: 1.40 inches.
September is a fall month in Rapid City, and is warmer than the annual average of 48°F. Daily temperatures swing about 23.2°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 12h 17m. For travel, September is one of the best months of the year to visit.
Avg High
74.0°F
Avg Low
50.8°F
Precipitation
1.40 in
Snow
0.1 in
September records in Rapid City
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 100.0°F (2012) | 46.0°F (2006) | 0.55 in (2006) |
| September 2 | 100.9°F (2023) | 42.1°F (2008) | 0.39 in (1996) |
| September 3 | 98.1°F (2005) | 42.1°F (2008) | 0.67 in (2004) |
| September 4 | 99.0°F (2001) | 44.1°F (1999) | 0.47 in (1997) |
| September 5 | 102.0°F (2020) | 43.0°F (1999) | 0.91 in (2004) |
| September 6 | 97.0°F (2021) | 45.0°F (2023) | 0.67 in (1996) |
| September 7 | 96.1°F (2022) | 30.9°F (2020) | 0.97 in (2020) |
| September 8 | 93.0°F (2005) | 30.9°F (2020) | 0.54 in (2013) |
| September 9 | 99.0°F (1998) | 32.0°F (2020) | 1.04 in (2002) |
| September 10 | 97.0°F (2012) | 35.1°F (2014) | 0.85 in (2003) |
| September 11 | 95.0°F (2024) | 32.0°F (2014) | 0.52 in (2019) |
| September 12 | 96.1°F (2004) | 32.0°F (2014) | 1.20 in (2009) |
| September 13 | 91.9°F (2015) | 33.1°F (2014) | 1.62 in (1998) |
| September 14 | 93.9°F (2020) | 34.0°F (2007) | 0.28 in (2001) |
| September 15 | 93.0°F (2019) | 37.9°F (2011) | 0.55 in (2017) |
| September 16 | 91.0°F (2000) | 37.0°F (2011) | 0.19 in (2022) |
| September 17 | 93.9°F (2000) | 35.1°F (2010) | 0.55 in (1996) |
| September 18 | 96.1°F (2004) | 34.0°F (2010) | 0.61 in (2002) |
| September 19 | 93.9°F (2022) | 33.1°F (2006) | 0.27 in (2000) |
| September 20 | 88.0°F (2007) | 36.0°F (2006) | 0.38 in (2019) |
| September 21 | 86.0°F (2013) | 39.0°F (1998) | 0.57 in (1998) |
| September 22 | 91.9°F (2007) | 30.9°F (2000) | 0.92 in (2006) |
| September 23 | 87.1°F (2011) | 28.9°F (2000) | 0.45 in (2006) |
| September 24 | 93.0°F (2020) | 30.9°F (2000) | 0.20 in (2005) |
| September 25 | 91.9°F (2008) | 33.1°F (1996) | 0.34 in (1996) |
| September 26 | 96.1°F (2024) | 36.0°F (1996) | 0.05 in (1999) |
| September 27 | 93.0°F (2021) | 35.1°F (1999) | 0.32 in (1999) |
| September 28 | 93.0°F (2021) | 35.1°F (1999) | 0.65 in (2019) |
| September 29 | 98.1°F (2024) | 32.0°F (1999) | 2.58 in (2014) |
| September 30 | 88.0°F (2025) | 37.9°F (2011) | 1.22 in (2014) |