Boone County, IL
: September 2026 so far averaged 66.8°F in Boone County, IL, the warmest 1 to 29 September in the county average since 2024, tied 6th warmest of 76 (with 2024) (county average from NOAA gridded data, 1951 to 2026).
Last updated . This page normally updates every day; the latest update is late.
- High
- 75.7°F
- Warmest since 2025
- 17th warmest of 76
- Low
- 47.4°F
- Warmest since 2025
- 34th warmest of 76
No measurable precipitation in the county average of Boone County, IL for 6 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 57.3 to 78.2°F
Every year as a table
Every 29 September low of the county average in Boone County, IL since 1951: 47.4°F in 2026; the lowest is 30°F, in 1984.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 75.7 | 47.4 |
| 2025 | 82.7 | 54.8 |
| 2024 | 78.1 | 58.6 |
| 2023 | 69.3 | 52 |
| 2022 | 59.1 | 36.4 |
| 2021 | 78 | 50.6 |
| 2020 | 60.8 | 42.3 |
| 2019 | 62.6 | 53.9 |
| 2018 | 57.4 | 37 |
| 2017 | 71.5 | 44.1 |
| 2016 | 62.2 | 49.6 |
| 2015 | 78 | 58.3 |
| 2014 | 80.6 | 52 |
| 2013 | 81.7 | 49 |
| 2012 | 69.4 | 40.6 |
| 2011 | 66.3 | 47.1 |
| 2010 | 71.7 | 46.8 |
| 2009 | 61.7 | 44.8 |
| 2008 | 67.7 | 51.8 |
| 2007 | 75.2 | 46 |
| 2006 | 57.8 | 39 |
| 2005 | 68.5 | 39.4 |
| 2004 | 65.5 | 39.8 |
| 2003 | 56 | 35.9 |
| 2002 | 76.4 | 50 |
| 2001 | 57.6 | 43.7 |
| 2000 | 67.6 | 42 |
| 1999 | 56.2 | 46.9 |
| 1998 | 76.2 | 50.4 |
| 1997 | 71.7 | 51.6 |
| 1996 | 62.6 | 47.6 |
| 1995 | 80.4 | 50.8 |
| 1994 | 63.8 | 41.1 |
| 1993 | 56.7 | 38.7 |
| 1992 | 57.5 | 33 |
| 1991 | 64.9 | 35.3 |
| 1990 | 65.4 | 46.5 |
| 1989 | 72.7 | 43.2 |
| 1988 | 69.5 | 55.2 |
| 1987 | 76.4 | 51.9 |
| 1986 | 78.8 | 62.5 |
| 1985 | 74 | 48.3 |
| 1984 | 54.5 | 30 |
| 1983 | 80.4 | 53.2 |
| 1982 | 74.3 | 51 |
| 1981 | 62.1 | 39.8 |
| 1980 | 65.5 | 46.6 |
| 1979 | 81.2 | 53 |
| 1978 | 67.2 | 43.9 |
| 1977 | 69.9 | 47.7 |
| 1976 | 65.2 | 43.1 |
| 1975 | 69.2 | 45.7 |
| 1974 | 67.5 | 44.5 |
| 1973 | 66 | 59.9 |
| 1972 | 70.7 | 42.1 |
| 1971 | 83.4 | 57.9 |
| 1970 | 63.9 | 36.8 |
| 1969 | 65.9 | 43 |
| 1968 | 67.3 | 47.4 |
| 1967 | 50.2 | 35.8 |
| 1966 | 63.3 | 50.9 |
| 1965 | 72.6 | 53.8 |
| 1964 | 64.1 | 33.5 |
| 1963 | 62 | 42.5 |
| 1962 | 63.7 | 36.2 |
| 1961 | 58.4 | 33.4 |
| 1960 | 65.1 | 46.5 |
| 1959 | 65.8 | 47.6 |
| 1958 | 67.1 | 41.6 |
| 1957 | 67.6 | 33.3 |
| 1956 | 75.6 | 55.1 |
| 1955 | 70.4 | 49.6 |
| 1954 | 75.5 | 59.6 |
| 1953 | 90.5 | 54.8 |
| 1952 | 79.6 | 51.7 |
| 1951 | 58.3 | 32 |
The month
August 2026 averaged 70.8°F in Boone County, IL, the warmest August in the county average since 2024, tied 59th warmest of 132 (with 1962) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 75.7°F averaged over Boone County, IL, the warmest 29 September in the county average since 2025, 17th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Tuesday 29 September 2026: a low of 47.4°F averaged over Boone County, IL, the warmest 29 September night in the county average since 2025, tied 34th warmest of 76 (with 1968) (county average from NOAA gridded data, 1951 to 2026).
- Days of the month without a value
- 0
Nearby
Rockford, IL 16.3 mi, the nearest city with its own station