Williamson County, IL
: September 2026 so far averaged 77.1°F in Williamson County, IL, the warmest 1 to 29 September in the county average since the data begin in 1951 (county average from NOAA gridded data, 1951 to 2026).
Last updated . This page normally updates every day; the latest update is late.
- High
- 81.1°F
- Warmest since 2025
- 25th warmest of 76
- Low
- 50.5°F
- Warmest since 2025
- 34th warmest of 76
No measurable precipitation in the county average of Williamson County, IL for 17 days to Tuesday 29 September 2026, the longest such spell in the county average since 2024 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 67.1 to 84.6°F
Every year as a table
Every 29 September low of the county average in Williamson County, IL since 1951: 50.5°F in 2026; the lowest is 36.7°F, in 1951.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 81.1 | 50.5 |
| 2025 | 85.4 | 55.8 |
| 2024 | 68.8 | 63.6 |
| 2023 | 82.3 | 62.6 |
| 2022 | 67.5 | 40.2 |
| 2021 | 85.3 | 59.9 |
| 2020 | 67 | 46.5 |
| 2019 | 88.3 | 67.6 |
| 2018 | 74.4 | 49.5 |
| 2017 | 77.7 | 49.9 |
| 2016 | 68.7 | 52.1 |
| 2015 | 79.3 | 62.4 |
| 2014 | 83.8 | 55.2 |
| 2013 | 81.6 | 59.5 |
| 2012 | 72.3 | 49.4 |
| 2011 | 75.5 | 51.7 |
| 2010 | 75.8 | 44.5 |
| 2009 | 71.1 | 46.3 |
| 2008 | 84.2 | 52.9 |
| 2007 | 84.1 | 51.7 |
| 2006 | 65.5 | 42.5 |
| 2005 | 79.8 | 46.5 |
| 2004 | 77.5 | 45.7 |
| 2003 | 63.9 | 38.5 |
| 2002 | 82.1 | 56 |
| 2001 | 67.1 | 44.4 |
| 2000 | 75.1 | 44.7 |
| 1999 | 90.5 | 52.4 |
| 1998 | 88.6 | 61.5 |
| 1997 | 79.8 | 51.6 |
| 1996 | 68.1 | 43 |
| 1995 | 79.9 | 47.4 |
| 1994 | 74.6 | 43.3 |
| 1993 | 72.4 | 42 |
| 1992 | 73 | 40 |
| 1991 | 79 | 47.1 |
| 1990 | 84.8 | 56.8 |
| 1989 | 73 | 43.1 |
| 1988 | 79 | 57.4 |
| 1987 | 84.2 | 59.1 |
| 1986 | 90.5 | 68.5 |
| 1985 | 73.5 | 44.6 |
| 1984 | 61.4 | 41.6 |
| 1983 | 84.3 | 50.3 |
| 1982 | 78.5 | 50.7 |
| 1981 | 74 | 46.4 |
| 1980 | 72.1 | 50.3 |
| 1979 | 82.4 | 58.1 |
| 1978 | 71.7 | 44.4 |
| 1977 | 72.4 | 51.3 |
| 1976 | 70.2 | 50.8 |
| 1975 | 70.3 | 44.3 |
| 1974 | 71.2 | 47.5 |
| 1973 | 81.9 | 67 |
| 1972 | 80.8 | 61.6 |
| 1971 | 88.9 | 66.4 |
| 1970 | 75 | 44.6 |
| 1969 | 76.7 | 44.2 |
| 1968 | 80.7 | 48.9 |
| 1967 | 57.5 | 38.4 |
| 1966 | 72.4 | 46.8 |
| 1965 | 78.7 | 51.2 |
| 1964 | 66.3 | 48.8 |
| 1963 | 77.4 | 50 |
| 1962 | 69 | 37.3 |
| 1961 | 75.5 | 43.4 |
| 1960 | 82 | 48.5 |
| 1959 | 80.8 | 61.6 |
| 1958 | 68 | 43.8 |
| 1957 | 72.2 | 42.2 |
| 1956 | 84 | 44.7 |
| 1955 | 89.1 | 60.2 |
| 1954 | 83.6 | 67 |
| 1953 | 97.1 | 52.5 |
| 1952 | 88.6 | 50.9 |
| 1951 | 65.8 | 36.7 |
The month
August 2026 averaged 77°F in Williamson County, IL, the warmest August in the county average since 2016, tied 34th warmest of 132 (with 1959, 1955 and 1906) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 81.1°F averaged over Williamson County, IL, the warmest 29 September in the county average since 2025, 25th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Tuesday 29 September 2026: a low of 50.5°F averaged over Williamson County, IL, the warmest 29 September night in the county average since 2025, 34th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Days of the month without a value
- 0
Nearby
Carbondale, IL 17.6 mi, the nearest city with its own station