Grundy County, IL
: September 2026 so far averaged 70.5°F in Grundy 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
- 76°F
- Warmest since 2025
- 26th warmest of 76
- Low
- 48°F
- Warmest since 2025
- 36th warmest of 76
No measurable precipitation in the county average of Grundy County, IL for 6 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 61.8 to 81.2°F
Every year as a table
Every 29 September low of the county average in Grundy County, IL since 1951: 48°F in 2026; the lowest is 32.4°F, in 1951.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 76 | 48 |
| 2025 | 86.9 | 56.1 |
| 2024 | 73 | 62.3 |
| 2023 | 73.3 | 53.8 |
| 2022 | 63.7 | 37.1 |
| 2021 | 80.4 | 54 |
| 2020 | 64.8 | 44.1 |
| 2019 | 68.1 | 60 |
| 2018 | 66.8 | 38.8 |
| 2017 | 73.2 | 47.8 |
| 2016 | 63 | 50.6 |
| 2015 | 78.9 | 60.9 |
| 2014 | 82.1 | 53.7 |
| 2013 | 84.1 | 50.5 |
| 2012 | 70.8 | 43.6 |
| 2011 | 67.4 | 49 |
| 2010 | 72.7 | 45.4 |
| 2009 | 63.7 | 47.1 |
| 2008 | 76.6 | 53.4 |
| 2007 | 77.3 | 47.7 |
| 2006 | 60.1 | 39.8 |
| 2005 | 75.4 | 42.1 |
| 2004 | 69.2 | 45.3 |
| 2003 | 57.7 | 37.5 |
| 2002 | 79.5 | 50.3 |
| 2001 | 57.5 | 45.9 |
| 2000 | 69 | 44 |
| 1999 | 67.3 | 50.7 |
| 1998 | 81.2 | 53.7 |
| 1997 | 72 | 51.2 |
| 1996 | 64.2 | 45.8 |
| 1995 | 81.6 | 50.6 |
| 1994 | 66.6 | 43.5 |
| 1993 | 62 | 38.6 |
| 1992 | 62.5 | 35.9 |
| 1991 | 68.3 | 43 |
| 1990 | 70.6 | 52.1 |
| 1989 | 73.9 | 42.9 |
| 1988 | 79.5 | 57.6 |
| 1987 | 80.1 | 56 |
| 1986 | 85.4 | 66 |
| 1985 | 76.5 | 47.8 |
| 1984 | 58.1 | 34.9 |
| 1983 | 80.1 | 52.7 |
| 1982 | 77.6 | 51.5 |
| 1981 | 66.2 | 42.5 |
| 1980 | 69.1 | 47.2 |
| 1979 | 83.2 | 53.1 |
| 1978 | 69.4 | 42 |
| 1977 | 72.5 | 45.4 |
| 1976 | 66.7 | 44 |
| 1975 | 72.4 | 48.5 |
| 1974 | 67.3 | 46 |
| 1973 | 76.8 | 62.1 |
| 1972 | 76.6 | 48.8 |
| 1971 | 85.2 | 65.5 |
| 1970 | 67.7 | 37.7 |
| 1969 | 72.4 | 42.9 |
| 1968 | 70.5 | 47.4 |
| 1967 | 52 | 35.2 |
| 1966 | 65.8 | 49 |
| 1965 | 76.5 | 51.3 |
| 1964 | 64.7 | 35.7 |
| 1963 | 71.5 | 45.3 |
| 1962 | 66.5 | 35.7 |
| 1961 | 63.5 | 34.7 |
| 1960 | 69.5 | 46.8 |
| 1959 | 70.8 | 53.3 |
| 1958 | 68.5 | 41.3 |
| 1957 | 68.6 | 34.7 |
| 1956 | 81.4 | 52.4 |
| 1955 | 72.5 | 50.1 |
| 1954 | 78.3 | 62.2 |
| 1953 | 94.5 | 56.1 |
| 1952 | 82.4 | 52.2 |
| 1951 | 60.6 | 32.4 |
The month
August 2026 averaged 72.7°F in Grundy County, IL, the warmest August in the county average since 2024, tied 43rd warmest of 132 (with 1944 and 1896) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 76°F averaged over Grundy County, IL, the warmest 29 September in the county average since 2025, 26th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Tuesday 29 September 2026: a low of 48°F averaged over Grundy County, IL, the warmest 29 September night in the county average since 2025, 36th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Days of the month without a value
- 0
Nearby
Chicago, IL 52.1 mi, the nearest city with its own station