September weather in Rock Springs, WY
The average temperature in Rock Springs in September is 58.1°F (41.2°F–75.0°F). Average precipitation: 1.17 inches.
September is a fall month in Rock Springs, and is warmer than the annual average of 45°F. Daily temperatures swing about 33.8°F between overnight low and afternoon high. Expect about 6 days with precipitation. Daylight averages about 12h 16m. For travel, September is a comfortable month to visit.
Avg High
75.0°F
Avg Low
41.2°F
Precipitation
1.17 in
Daylight
12h 16m
September records in Rock Springs
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 91.0°F (2019) | 35.1°F (2005) | 1.15 in (2008) |
| September 2 | 91.0°F (2019) | 36.0°F (2008) | 0.04 in (2003) |
| September 3 | 91.9°F (2022) | 37.0°F (2010) | 0.27 in (2021) |
| September 4 | 93.0°F (2022) | 37.9°F (2008) | 0.54 in (2023) |
| September 5 | 91.9°F (2020) | 39.0°F (2021) | 0.30 in (2007) |
| September 6 | 93.0°F (2022) | 37.0°F (2008) | 0.18 in (2013) |
| September 7 | 93.9°F (2022) | 30.0°F (2010) | 0.16 in (2025) |
| September 8 | 91.0°F (2022) | 24.1°F (2020) | 0.49 in (2005) |
| September 9 | 89.1°F (2021) | 24.1°F (2020) | 0.34 in (2014) |
| September 10 | 88.0°F (2021) | 30.0°F (2020) | 0.40 in (2012) |
| September 11 | 84.0°F (2004) | 32.0°F (2016) | 0.43 in (2013) |
| September 12 | 84.9°F (2018) | 26.1°F (2014) | 0.37 in (2013) |
| September 13 | 84.0°F (2015) | 28.9°F (2005) | 0.39 in (2021) |
| September 14 | 84.0°F (2015) | 28.9°F (2003) | 0.45 in (2016) |
| September 15 | 84.0°F (2018) | 32.0°F (2003) | 0.50 in (2013) |
| September 16 | 84.0°F (2019) | 33.1°F (2006) | 0.08 in (2025) |
| September 17 | 84.0°F (2014) | 28.9°F (2017) | 0.15 in (2024) |
| September 18 | 84.9°F (2014) | 27.0°F (2003) | 0.05 in (2003) |
| September 19 | 86.0°F (2010) | 30.0°F (2003) | 0.20 in (2017) |
| September 20 | 84.9°F (2010) | 30.9°F (2013) | 0.66 in (2004) |
| September 21 | 81.0°F (2014) | 28.0°F (2021) | 0.24 in (2006) |
| September 22 | 81.0°F (2015) | 27.0°F (2009) | 1.07 in (2016) |
| September 23 | 82.0°F (2015) | 34.0°F (2023) | 0.55 in (2007) |
| September 24 | 84.0°F (2020) | 30.9°F (2008) | 0.10 in (2007) |
| September 25 | 84.9°F (2015) | 28.0°F (2018) | 0.13 in (2007) |
| September 26 | 84.9°F (2010) | 28.0°F (2017) | 0.31 in (2012) |
| September 27 | 84.0°F (2010) | 30.9°F (2017) | 0.63 in (2013) |
| September 28 | 84.9°F (2010) | 26.1°F (2020) | 1.35 in (2014) |
| September 29 | 84.9°F (2010) | 33.1°F (2005) | 0.46 in (2019) |
| September 30 | 80.1°F (2008) | 30.9°F (2007) | 0.62 in (2009) |