August weather in Seneca, IL
The average temperature in Seneca in August is 71.5°F (60.5°F–82.4°F). Average precipitation: 4.09 inches.
August is a summer month in Seneca, and is warmer than the annual average of 49.7°F. Daily temperatures swing about 21.9°F between overnight low and afternoon high. Expect about 9 days with precipitation. Daylight averages about 13h 40m. For travel, August is a comfortable month to visit.
Avg High
82.4°F
Avg Low
60.5°F
Precipitation
4.09 in
Daylight
13h 40m
August records in Seneca
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| August 1 | 97.0°F (2006) | 52.0°F (1997) | 1.30 in (1941) |
| August 2 | 97.0°F (2006) | 52.0°F (2009) | 1.15 in (1961) |
| August 3 | 98.1°F (2006) | 52.0°F (2009) | 2.08 in (1943) |
| August 4 | 96.1°F (2012) | 54.0°F (2015) | 2.26 in (1960) |
| August 5 | 97.0°F (2012) | 51.1°F (2020) | 1.17 in (2016) |
| August 6 | 91.0°F (2024) | 48.0°F (1997) | 1.65 in (2023) |
| August 7 | 91.0°F (2007) | 48.9°F (1997) | 1.60 in (1986) |
| August 8 | 91.9°F (2001) | 51.1°F (2004) | 1.06 in (1977) |
| August 9 | 90.0°F (2001) | 46.9°F (2020) | 0.78 in (1965) |
| August 10 | 93.9°F (2005) | 51.1°F (1999) | 1.56 in (1995) |
| August 11 | 91.9°F (2020) | 48.9°F (2012) | 1.46 in (1994) |
| August 12 | 91.9°F (2020) | 48.9°F (2012) | 5.23 in (1949) |
| August 13 | 91.9°F (2010) | 48.0°F (2004) | 2.61 in (2016) |
| August 14 | 91.9°F (2010) | 46.9°F (2004) | 1.97 in (1945) |
| August 15 | 91.9°F (2010) | 46.0°F (2004) | 2.60 in (1981) |
| August 16 | 90.0°F (2025) | 46.9°F (2004) | 1.34 in (1970) |
| August 17 | 93.9°F (2025) | 48.0°F (2004) | 1.30 in (1946) |
| August 18 | 88.0°F (2025) | 48.9°F (2012) | 1.86 in (1979) |
| August 19 | 91.0°F (2025) | 48.9°F (2012) | 1.47 in (2002) |
| August 20 | 89.1°F (2011) | 51.1°F (2012) | 3.50 in (1979) |
| August 21 | 91.9°F (2010) | 48.0°F (2024) | 1.89 in (1958) |
| August 22 | 95.0°F (2003) | 48.9°F (2004) | 4.12 in (2014) |
| August 23 | 89.1°F (2007) | 50.0°F (1997) | 3.12 in (2013) |
| August 24 | 96.1°F (2023) | 51.1°F (1997) | 6.00 in (2007) |
| August 25 | 97.0°F (2023) | 46.9°F (2017) | 1.94 in (2016) |
| August 26 | 93.9°F (2003) | 46.9°F (2017) | 3.05 in (1987) |
| August 27 | 93.9°F (2003) | 50.0°F (2025) | 3.60 in (1942) |
| August 28 | 95.0°F (2024) | 51.1°F (2023) | 2.21 in (2009) |
| August 29 | 97.0°F (2007) | 51.1°F (2023) | 2.16 in (2006) |
| August 30 | 93.0°F (2010) | 51.1°F (2004) | 2.28 in (1955) |
| August 31 | 91.9°F (2012) | 45.0°F (2009) | 2.75 in (1980) |