September weather in State Line, ID
The average temperature in State Line in September is °F (°F–°F). Average precipitation: 1.93 inches.
September is a fall month in State Line, and is cooler than the annual average of 0°F. Expect about 6 days with precipitation. Daylight averages about 12h 20m.
Avg High
°F
Avg Low
°F
Precipitation
1.93 in
Daylight
12h 20m
September records in State Line
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 86.7°F (2025) | 43.0°F (2008) | 0.30 in (2010) |
| September 2 | 90.7°F (2025) | 43.7°F (2010) | 0.20 in (2011) |
| September 3 | 87.8°F (2025) | 41.5°F (2014) | 1.00 in (2014) |
| September 4 | 82.6°F (2025) | 41.5°F (2015) | 0.10 in (2013) |
| September 5 | 81.0°F (2024) | 39.7°F (2010) | 0.60 in (2013) |
| September 6 | 81.7°F (2024) | 39.9°F (2015) | 0.30 in (2013) |
| September 7 | 83.3°F (2024) | 40.5°F (2009) | 0.20 in (2016) |
| September 8 | 80.8°F (2011) | 39.7°F (2020) | 0.20 in (2013) |
| September 9 | 81.3°F (2011) | 43.2°F (2016) | 0.60 in (2019) |
| September 10 | 81.5°F (2011) | 35.8°F (2014) | 0.50 in (2019) |
| September 11 | 80.8°F (2011) | 33.3°F (2014) | 1.20 in (2021) |
| September 12 | 79.3°F (2013) | 37.9°F (2016) | 0.10 in (2010) |
| September 13 | 78.1°F (2013) | 38.5°F (2016) | 0.10 in (2025) |
| September 14 | 77.0°F (2013) | 43.3°F (2017) | 0.10 in (2016) |
| September 15 | 76.5°F (2013) | 37.4°F (2015) | 0.20 in (2013) |
| September 16 | 78.8°F (2009) | 38.5°F (2017) | 0.20 in (2010) |
| September 17 | 78.1°F (2008) | 39.4°F (2011) | 1.30 in (2013) |
| September 18 | 77.0°F (2008) | 39.0°F (2017) | 1.40 in (2021) |
| September 19 | 77.5°F (2025) | 36.3°F (2017) | 1.70 in (2010) |
| September 20 | 74.8°F (2012) | 36.7°F (2017) | 0.30 in (2017) |
| September 21 | 75.4°F (2012) | 35.4°F (2017) | 1.10 in (2008) |
| September 22 | 72.5°F (2014) | 35.8°F (2017) | 0.20 in (2013) |
| September 23 | 80.6°F (2009) | 35.6°F (2008) | 0.10 in (2007) |
| September 24 | 79.2°F (2011) | 39.7°F (2008) | 0.70 in (2013) |
| September 25 | 72.9°F (2009) | 38.7°F (2013) | 0.30 in (2020) |
| September 26 | 73.2°F (2022) | 37.8°F (2013) | 0.50 in (2023) |
| September 27 | 77.7°F (2022) | 39.2°F (2013) | 0.80 in (2021) |
| September 28 | 73.2°F (2025) | 28.2°F (2019) | 1.20 in (2013) |
| September 29 | 73.2°F (2006) | 28.0°F (2019) | 0.70 in (2013) |
| September 30 | 69.3°F (2015) | 28.6°F (2019) | 0.60 in (2007) |