Mercer County, IL
: September 2026 so far averaged 70.3°F in Mercer County, IL, the warmest 1 to 29 September in the county average since 2016, 3rd 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
- 77.2°F
- Warmest since 2025
- 21st warmest of 76
- Low
- 48.1°F
- Warmest since 2025
- 34th warmest of 76
No measurable precipitation in the county average of Mercer County, IL for 2 days to Tuesday 29 September 2026 (county average from NOAA gridded data, 1951 to 2026).
- Normal range, 59.1 to 80.3°F
Every year as a table
Every 29 September low of the county average in Mercer County, IL since 1951: 48.1°F in 2026; the lowest is 33°F, in 1984.
| Year | High, °F | Low, °F |
|---|---|---|
| 2026 | 77.2 | 48.1 |
| 2025 | 88.3 | 55.6 |
| 2024 | 81 | 57.2 |
| 2023 | 75.6 | 58 |
| 2022 | 63.7 | 38.5 |
| 2021 | 84.6 | 57.5 |
| 2020 | 63.7 | 45.3 |
| 2019 | 67.7 | 56.6 |
| 2018 | 56.3 | 41 |
| 2017 | 74.4 | 45.4 |
| 2016 | 65.2 | 49.8 |
| 2015 | 82.4 | 60.1 |
| 2014 | 83.1 | 54.6 |
| 2013 | 78.1 | 46.3 |
| 2012 | 70 | 40.1 |
| 2011 | 68.2 | 48 |
| 2010 | 74.3 | 48 |
| 2009 | 61.8 | 47.6 |
| 2008 | 76.3 | 56.4 |
| 2007 | 77.8 | 49.8 |
| 2006 | 61.4 | 42.8 |
| 2005 | 66.3 | 41.6 |
| 2004 | 68.3 | 41.7 |
| 2003 | 57.4 | 36.9 |
| 2002 | 80.2 | 54.1 |
| 2001 | 65.7 | 43.4 |
| 2000 | 73 | 47.3 |
| 1999 | 56.4 | 46 |
| 1998 | 80.7 | 57.8 |
| 1997 | 75.5 | 53.1 |
| 1996 | 66.4 | 46 |
| 1995 | 79.6 | 52.5 |
| 1994 | 71 | 44.3 |
| 1993 | 63.9 | 38.9 |
| 1992 | 59.3 | 36.9 |
| 1991 | 69.4 | 41.9 |
| 1990 | 72.8 | 51.8 |
| 1989 | 75 | 40.5 |
| 1988 | 76 | 59 |
| 1987 | 78.2 | 55.3 |
| 1986 | 82.5 | 65.2 |
| 1985 | 72.2 | 49.7 |
| 1984 | 52.6 | 33 |
| 1983 | 83.3 | 57 |
| 1982 | 78.5 | 55.4 |
| 1981 | 66.7 | 41.1 |
| 1980 | 75.5 | 46.3 |
| 1979 | 83.9 | 54 |
| 1978 | 68 | 43.1 |
| 1977 | 71.7 | 47.9 |
| 1976 | 62.8 | 50.4 |
| 1975 | 68 | 45.3 |
| 1974 | 68.5 | 44.6 |
| 1973 | 76 | 63.4 |
| 1972 | 73.3 | 43 |
| 1971 | 87.1 | 63.5 |
| 1970 | 71.4 | 40.6 |
| 1969 | 75.1 | 46.5 |
| 1968 | 69 | 47.2 |
| 1967 | 55.9 | 33.1 |
| 1966 | 67.9 | 49.5 |
| 1965 | 75.8 | 52.7 |
| 1964 | 65.7 | 36.2 |
| 1963 | 75.7 | 46.7 |
| 1962 | 68.2 | 36.5 |
| 1961 | 63.7 | 37.1 |
| 1960 | 70 | 48.5 |
| 1959 | 65.8 | 46.8 |
| 1958 | 69.8 | 41.5 |
| 1957 | 68.4 | 34.9 |
| 1956 | 79.3 | 53.5 |
| 1955 | 76.3 | 54.7 |
| 1954 | 79.6 | 62.7 |
| 1953 | 96.1 | 59.2 |
| 1952 | 86.1 | 54.4 |
| 1951 | 58.9 | 34.1 |
The month
August 2026 averaged 73.6°F in Mercer County, IL, the warmest August in the county average since 2021, tied 40th warmest of 132 (with 1960, 1928, 1926 and 1 other year) (county average from NOAA's monthly county data, 1895 to 2026).
The month in words
- Tuesday 29 September 2026: a high of 77.2°F averaged over Mercer 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 48.1°F averaged over Mercer 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
Moline, IL 20.2 mi, the nearest city with its own station