August weather in St. Johns, IL
The average temperature in St. Johns in August is 75.7°F (64.9°F–86.4°F). Average precipitation: 3.30 inches.
August is a summer month in St. Johns, and is warmer than the annual average of 56°F. Daily temperatures swing about 21.5°F between overnight low and afternoon high. Expect about 7 days with precipitation. Daylight averages about 13h 29m. For travel, August is a comfortable month to visit.
Avg High
86.4°F
Avg Low
64.9°F
Precipitation
3.30 in
Daylight
13h 29m
August records in St. Johns
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| August 1 | 102.0°F (2012) | 51.1°F (1971) | 1.85 in (1934) |
| August 2 | 102.9°F (1901) | 51.1°F (1977) | 1.45 in (1980) |
| August 3 | 107.1°F (1918) | 50.0°F (1920) | 2.13 in (2000) |
| August 4 | 109.0°F (1918) | 50.0°F (1912) | 4.77 in (2015) |
| August 5 | 109.0°F (1918) | 50.0°F (1912) | 4.96 in (2022) |
| August 6 | 109.0°F (1930) | 50.0°F (1994) | 1.50 in (1908) |
| August 7 | 107.1°F (1930) | 50.0°F (1989) | 2.05 in (1906) |
| August 8 | 111.9°F (1930) | 48.0°F (1978) | 2.37 in (1898) |
| August 9 | 113.0°F (1930) | 51.1°F (1976) | 3.40 in (1963) |
| August 10 | 102.9°F (1934) | 51.1°F (1972) | 1.65 in (1931) |
| August 11 | 106.0°F (1918) | 52.0°F (2012) | 1.15 in (1945) |
| August 12 | 102.0°F (1936) | 48.9°F (1967) | 3.02 in (1925) |
| August 13 | 100.9°F (1913) | 46.0°F (1964) | 2.04 in (1932) |
| August 14 | 102.0°F (1913) | 46.9°F (2004) | 1.80 in (2016) |
| August 15 | 105.1°F (1936) | 48.0°F (1929) | 2.35 in (2016) |
| August 16 | 104.0°F (1913) | 48.0°F (1929) | 2.40 in (1946) |
| August 17 | 107.1°F (1936) | 51.1°F (1994) | 5.38 in (1959) |
| August 18 | 109.0°F (1936) | 52.0°F (1943) | 3.10 in (1950) |
| August 19 | 108.0°F (1936) | 51.1°F (1943) | 1.45 in (1960) |
| August 20 | 105.1°F (1936) | 48.9°F (1967) | 5.04 in (1915) |
| August 21 | 111.0°F (1900) | 46.9°F (1950) | 1.47 in (2010) |
| August 22 | 106.0°F (1936) | 48.9°F (1940) | 0.97 in (1964) |
| August 23 | 102.0°F (1938) | 48.0°F (1920) | 3.35 in (1907) |
| August 24 | 102.0°F (1938) | 45.0°F (1920) | 1.10 in (1893) |
| August 25 | 106.0°F (1978) | 46.9°F (1927) | 1.22 in (1981) |
| August 26 | 102.9°F (1943) | 48.0°F (1958) | 1.20 in (1901) |
| August 27 | 108.0°F (1936) | 46.9°F (2025) | 1.58 in (2005) |
| August 28 | 104.0°F (1936) | 48.0°F (1967) | 1.77 in (1933) |
| August 29 | 100.9°F (1925) | 43.0°F (1986) | 2.05 in (1977) |
| August 30 | 99.0°F (1951) | 46.0°F (1946) | 2.38 in (1978) |
| August 31 | 100.9°F (1943) | 43.0°F (1915) | 2.00 in (1926) |