DeKalb County, IL
: September 2026 so far averaged 68°F in DeKalb County, IL, the warmest 1 to 29 September in the county average since 2016, 5th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
Last updated . This page normally updates every day; the latest update is late.
- High
- 75.3°F
- Warmest since 2025
- 21st warmest of 76
- Low
- 47.8°F
- Warmest since 2025
- 34th warmest of 76
No measurable precipitation in the county average of DeKalb County, IL for 6 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 58.4 to 78.4°F
Every year as a table
Every 29 September low of the county average in DeKalb County, IL since 1951: 47.8°F in 2026; the lowest is 31.6°F, in 1984.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 75.3 | 47.8 |
| 2025 | 84.4 | 56.3 |
| 2024 | 75.6 | 60.5 |
| 2023 | 70.8 | 53.2 |
| 2022 | 60.1 | 37.2 |
| 2021 | 79.3 | 52.2 |
| 2020 | 61.6 | 41.4 |
| 2019 | 62.9 | 55 |
| 2018 | 60.1 | 36.6 |
| 2017 | 72.6 | 45.1 |
| 2016 | 62.9 | 49.3 |
| 2015 | 78.2 | 59.9 |
| 2014 | 81.2 | 53 |
| 2013 | 82.1 | 49.2 |
| 2012 | 69.8 | 41.8 |
| 2011 | 67 | 47.1 |
| 2010 | 72.4 | 47 |
| 2009 | 62.3 | 45.6 |
| 2008 | 70.3 | 52.9 |
| 2007 | 75.9 | 46.8 |
| 2006 | 58.4 | 38.9 |
| 2005 | 71 | 39.7 |
| 2004 | 66.9 | 41.9 |
| 2003 | 55.7 | 35.4 |
| 2002 | 77.8 | 51.9 |
| 2001 | 57.6 | 45.2 |
| 2000 | 68.2 | 43.5 |
| 1999 | 58.2 | 48.2 |
| 1998 | 77.8 | 51.8 |
| 1997 | 71.3 | 50.9 |
| 1996 | 62.5 | 46.4 |
| 1995 | 80.1 | 50.6 |
| 1994 | 64.9 | 41.6 |
| 1993 | 59.1 | 38 |
| 1992 | 59.6 | 33.6 |
| 1991 | 66.5 | 37.9 |
| 1990 | 66.8 | 48.5 |
| 1989 | 73.2 | 42.7 |
| 1988 | 73.1 | 55.4 |
| 1987 | 77.1 | 53.2 |
| 1986 | 81.8 | 64.3 |
| 1985 | 74.8 | 46.8 |
| 1984 | 55.2 | 31.6 |
| 1983 | 80.4 | 54 |
| 1982 | 76 | 51.3 |
| 1981 | 63.8 | 40.5 |
| 1980 | 64.9 | 46.7 |
| 1979 | 82.3 | 52.5 |
| 1978 | 67.4 | 43.2 |
| 1977 | 71.8 | 47.3 |
| 1976 | 65.2 | 43.7 |
| 1975 | 70.4 | 46.7 |
| 1974 | 66.7 | 45.3 |
| 1973 | 69.4 | 61 |
| 1972 | 73.2 | 44.3 |
| 1971 | 83.1 | 61.7 |
| 1970 | 65.2 | 37.8 |
| 1969 | 67.8 | 43.7 |
| 1968 | 68.3 | 48 |
| 1967 | 50.8 | 36.2 |
| 1966 | 64.1 | 50.8 |
| 1965 | 74.4 | 53 |
| 1964 | 63.5 | 33.9 |
| 1963 | 65.5 | 43.3 |
| 1962 | 65.5 | 36.4 |
| 1961 | 61 | 34.1 |
| 1960 | 67.4 | 46.1 |
| 1959 | 67.2 | 49.1 |
| 1958 | 68.1 | 40.8 |
| 1957 | 68.5 | 34.3 |
| 1956 | 77.8 | 54.3 |
| 1955 | 71 | 49.2 |
| 1954 | 76.5 | 60.4 |
| 1953 | 92.9 | 55.2 |
| 1952 | 81.4 | 51.6 |
| 1951 | 59.6 | 32 |
The month
August 2026 averaged 71.4°F in DeKalb County, IL, the warmest August in the county average since 2021, tied 50th warmest of 132 (with 1928 and 1905) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 75.3°F averaged over DeKalb County, IL, the warmest 29 September in the county average since 2025, 21st warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Tuesday 29 September 2026: a low of 47.8°F averaged over DeKalb 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
Rockford, IL 26.5 mi, the nearest city with its own station