McHenry County, IL
: September 2026 so far averaged 66.6°F in McHenry County, IL, the warmest 1 to 29 September in the county average since 2021, tied 7th warmest of 76 (with 1998) (county average from NOAA gridded data, 1951 to 2026).
Last updated . This page normally updates every day; the latest update is late.
- High
- 74.7°F
- Warmest since 2025
- 17th warmest of 76
- Low
- 46.9°F
- Warmest since 2025
- 37th warmest of 76
No measurable precipitation in the county average of McHenry County, IL for 6 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 57.1 to 78.2°F
Every year as a table
Every 29 September low of the county average in McHenry County, IL since 1951: 46.9°F in 2026; the lowest is 31.4°F, in 1984.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 74.7 | 46.9 |
| 2025 | 80.5 | 54.2 |
| 2024 | 76.1 | 59.4 |
| 2023 | 68.4 | 51.3 |
| 2022 | 59.8 | 36.5 |
| 2021 | 76.1 | 49.3 |
| 2020 | 61.4 | 42.4 |
| 2019 | 62.7 | 54 |
| 2018 | 57.2 | 36.4 |
| 2017 | 72.8 | 45.5 |
| 2016 | 62.8 | 49.7 |
| 2015 | 78 | 58.2 |
| 2014 | 79.7 | 51.5 |
| 2013 | 81.4 | 48.5 |
| 2012 | 68.1 | 41.7 |
| 2011 | 63.9 | 47.7 |
| 2010 | 71 | 47 |
| 2009 | 61.1 | 44.6 |
| 2008 | 67.7 | 50.5 |
| 2007 | 74 | 46 |
| 2006 | 58.2 | 37.9 |
| 2005 | 69.2 | 39.4 |
| 2004 | 64.8 | 41.2 |
| 2003 | 55.8 | 36.6 |
| 2002 | 74.5 | 49.6 |
| 2001 | 56.6 | 43.8 |
| 2000 | 65.9 | 42.2 |
| 1999 | 58.3 | 48.1 |
| 1998 | 76.2 | 50.5 |
| 1997 | 70.8 | 51.8 |
| 1996 | 61.9 | 46.6 |
| 1995 | 79.9 | 50.7 |
| 1994 | 63.5 | 41.4 |
| 1993 | 56.3 | 38.5 |
| 1992 | 58 | 33.2 |
| 1991 | 63.7 | 34.6 |
| 1990 | 64.8 | 47.8 |
| 1989 | 72.6 | 43.6 |
| 1988 | 69.5 | 55 |
| 1987 | 76.2 | 52.2 |
| 1986 | 78.8 | 62.4 |
| 1985 | 74.1 | 47.4 |
| 1984 | 54.7 | 31.4 |
| 1983 | 80.1 | 52.6 |
| 1982 | 73 | 50.4 |
| 1981 | 61.7 | 39.8 |
| 1980 | 65.4 | 46.7 |
| 1979 | 81.7 | 52.7 |
| 1978 | 65.9 | 43.7 |
| 1977 | 69.2 | 46.7 |
| 1976 | 64.3 | 43.3 |
| 1975 | 69.5 | 44.9 |
| 1974 | 66.3 | 44.7 |
| 1973 | 65.5 | 59.8 |
| 1972 | 71.7 | 44 |
| 1971 | 83.5 | 58.7 |
| 1970 | 61.8 | 36.3 |
| 1969 | 65.3 | 42.5 |
| 1968 | 68 | 46.5 |
| 1967 | 49.2 | 37.1 |
| 1966 | 62.9 | 50.9 |
| 1965 | 72.6 | 53.6 |
| 1964 | 63.5 | 33.3 |
| 1963 | 61.5 | 43.2 |
| 1962 | 63.6 | 37.4 |
| 1961 | 58.2 | 33.3 |
| 1960 | 64.7 | 47.1 |
| 1959 | 66.5 | 49.1 |
| 1958 | 66.3 | 41.7 |
| 1957 | 66.8 | 33.7 |
| 1956 | 75.3 | 54.6 |
| 1955 | 69.9 | 48.9 |
| 1954 | 74.5 | 59.6 |
| 1953 | 89.8 | 53.5 |
| 1952 | 79.4 | 52.3 |
| 1951 | 57.7 | 31.8 |
The month
August 2026 averaged 70.9°F in McHenry County, IL, the warmest August in the county average since 2024, tied 52nd warmest of 132 (with 2022) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 74.7°F averaged over McHenry 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 46.9°F averaged over McHenry County, IL, the warmest 29 September night in the county average since 2025, 37th warmest of 76 (county average from NOAA gridded data, 1951 to 2026).
- Days of the month without a value
- 0
Nearby
Rockford, IL 34.0 mi, the nearest city with its own station