September weather in West Yellowstone, MT
The average temperature in West Yellowstone in September is °F (°F–°F). Average precipitation: 1.42 inches.
September is a fall month in West Yellowstone, and is cooler than the annual average of 0°F. Expect about 5 days with precipitation. Daylight averages about 12h 18m.
Avg High
°F
Avg Low
°F
Precipitation
1.42 in
Daylight
12h 18m
September records in West Yellowstone
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 90.5°F (2022) | 21.9°F (2006) | 0.60 in (2000) |
| September 2 | 89.2°F (2017) | 21.2°F (2006) | 0.10 in (2000) |
| September 3 | 92.5°F (2022) | 23.7°F (2010) | 0.40 in (2023) |
| September 4 | 89.6°F (2022) | 23.4°F (2004) | 0.20 in (2023) |
| September 5 | 90.0°F (2020) | 22.3°F (2008) | 0.20 in (2007) |
| September 6 | 91.2°F (2022) | 21.7°F (2010) | 0.70 in (2002) |
| September 7 | 92.1°F (2022) | 18.0°F (2010) | 0.20 in (2002) |
| September 8 | 86.0°F (2021) | 18.0°F (2008) | 0.40 in (2013) |
| September 9 | 88.0°F (2021) | 19.0°F (2009) | 0.20 in (2010) |
| September 10 | 81.1°F (2021) | 16.9°F (2007) | 0.30 in (2003) |
| September 11 | 83.7°F (2017) | 18.0°F (2014) | 0.10 in (2019) |
| September 12 | 84.6°F (2015) | 12.2°F (2014) | 0.50 in (2016) |
| September 13 | 81.3°F (2015) | 18.3°F (2014) | 0.50 in (2004) |
| September 14 | 82.4°F (2020) | 17.1°F (2003) | 0.90 in (2017) |
| September 15 | 85.8°F (2000) | 23.5°F (1999) | 0.60 in (2017) |
| September 16 | 82.8°F (2000) | 23.2°F (2007) | 0.90 in (2015) |
| September 17 | 82.0°F (2008) | 18.1°F (2021) | 0.90 in (2013) |
| September 18 | 84.0°F (2009) | 14.4°F (2003) | 0.40 in (2014) |
| September 19 | 79.9°F (2009) | 16.7°F (2003) | 0.80 in (2021) |
| September 20 | 77.4°F (2012) | 19.0°F (2000) | 0.50 in (2008) |
| September 21 | 79.5°F (2012) | 18.0°F (2003) | 0.70 in (2017) |
| September 22 | 79.0°F (2012) | 16.2°F (2002) | 0.90 in (2016) |
| September 23 | 81.3°F (2009) | 17.2°F (2000) | 0.40 in (2007) |
| September 24 | 83.3°F (2009) | 10.8°F (2000) | 0.30 in (2005) |
| September 25 | 82.8°F (2015) | 15.4°F (2000) | 0.20 in (2013) |
| September 26 | 80.4°F (2015) | 15.8°F (2018) | 0.30 in (2020) |
| September 27 | 81.5°F (2010) | 13.1°F (1999) | 1.00 in (2014) |
| September 28 | 81.3°F (2010) | 5.0°F (1999) | 0.30 in (2014) |
| September 29 | 79.5°F (2010) | 19.2°F (2020) | 0.40 in (2019) |
| September 30 | 80.6°F (2010) | 12.9°F (2021) | 0.40 in (2013) |