September weather in Lerna, IL
The average temperature in Lerna in September is 67.4°F (56.1°F–78.7°F). Average precipitation: 2.85 inches.
September is a fall month in Lerna, and is warmer than the annual average of 53.4°F. Daily temperatures swing about 22.6°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 12h 15m. For travel, September is one of the best months of the year to visit.
Avg High
78.7°F
Avg Low
56.1°F
Precipitation
2.85 in
Daylight
12h 15m
September records in Lerna
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | 99.0°F (2011) | 41.0°F (2007) | 1.22 in (2012) |
| September 2 | 98.1°F (2011) | 42.1°F (2017) | 2.41 in (2010) |
| September 3 | 96.1°F (2011) | 48.9°F (2024) | 0.18 in (2011) |
| September 4 | 95.0°F (1999) | 50.0°F (2024) | 1.09 in (2008) |
| September 5 | 96.1°F (1999) | 48.0°F (2003) | 0.71 in (2012) |
| September 6 | 93.9°F (1998) | 45.0°F (2011) | 0.49 in (2007) |
| September 7 | 93.0°F (2015) | 45.0°F (2025) | 2.60 in (2012) |
| September 8 | 93.9°F (2002) | 42.1°F (2024) | 1.72 in (2007) |
| September 9 | 95.0°F (2013) | 44.1°F (2024) | 0.64 in (2015) |
| September 10 | 96.1°F (2013) | 46.0°F (2017) | 3.95 in (2000) |
| September 11 | 95.0°F (2013) | 44.1°F (2017) | 0.57 in (2015) |
| September 12 | 91.9°F (1998) | 45.0°F (2007) | 1.17 in (2008) |
| September 13 | 93.0°F (2025) | 39.9°F (2014) | 0.09 in (2017) |
| September 14 | 96.1°F (2025) | 39.9°F (2014) | 1.11 in (2008) |
| September 15 | 91.0°F (2025) | 36.0°F (2007) | 0.47 in (2014) |
| September 16 | 91.0°F (2019) | 42.1°F (1999) | 0.85 in (2016) |
| September 17 | 91.9°F (2018) | 44.1°F (1999) | 0.65 in (2006) |
| September 18 | 91.9°F (2018) | 43.0°F (2020) | 0.59 in (2001) |
| September 19 | 91.9°F (2005) | 39.0°F (2020) | 0.51 in (2005) |
| September 20 | 93.0°F (2017) | 39.0°F (2006) | 0.88 in (1998) |
| September 21 | 95.0°F (2017) | 39.9°F (1999) | 0.83 in (2023) |
| September 22 | 93.9°F (2017) | 39.0°F (1999) | 0.50 in (2003) |
| September 23 | 93.0°F (2017) | 39.9°F (2012) | 0.29 in (2024) |
| September 24 | 91.9°F (2017) | 36.0°F (2012) | 0.41 in (2000) |
| September 25 | 91.0°F (2017) | 34.0°F (2001) | 2.30 in (2018) |
| September 26 | 91.0°F (2017) | 37.9°F (2000) | 1.94 in (2003) |
| September 27 | 91.9°F (1998) | 42.1°F (2010) | 0.85 in (2024) |
| September 28 | 89.1°F (2025) | 37.0°F (2022) | 1.43 in (1999) |
| September 29 | 91.0°F (2025) | 37.9°F (2022) | 0.55 in (2015) |
| September 30 | 90.0°F (2019) | 39.0°F (2005) | 0.62 in (2016) |