# Cooling degree days in Illinois

Cooling degree days in Illinois was 1,038 degree days (base 65°F) in 2025. Source: NOAA National Centers for Environmental Information.

- Indicator id: `cooling_degree_days_annual`
- Place id: `us-state-17`
- Unit: degree days (base 65°F)
- Definition: Sum over January to December of the degrees by which the daily mean temperature exceeds 65°F, a measure of cooling demand. NOAA estimates monthly values from nClimDiv temperatures and weights areas by population (2010 Census).
- Note: NOAA publishes these for operational monitoring; they can differ from official degree day publications.
- Source: NOAA National Centers for Environmental Information, NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide (https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/11/cdd/12/12/1895-2025/data.json)
- Publisher page: https://invokely.ai/en/publishers/noaa-ncei
- Retrieved: 2026-10-12
- License: Public domain (US government work); NCEI asks users to cite the nClimDiv dataset
- Citation: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/11/cdd/12/12/1895-2025/data.json. Retrieved 2026-10-12.
- Web page: https://invokely.ai/en/cooling-degree-days/illinois
- API: https://invokely.ai/api/v1/series?indicator=cooling_degree_days_annual&place=us-state-17

| Period | degree days (base 65°F) |
|---|---:|
| 2025 | 1,038 |
| 2024 | 1,024 |
| 2023 | 881 |
| 2022 | 929 |
| 2021 | 1,063 |
| 2020 | 951 |
| 2019 | 936 |
| 2018 | 1,096 |
| 2017 | 840 |
| 2016 | 1,089 |
| 2015 | 842 |
| 2014 | 725 |
| 2013 | 805 |
| 2012 | 1,156 |
| 2011 | 982 |
| 2010 | 1,113 |
| 2009 | 623 |
| 2008 | 792 |
| 2007 | 1,052 |
| 2006 | 870 |
| 2005 | 1,108 |
| 2004 | 679 |
| 2003 | 752 |
| 2002 | 1,020 |
| 2001 | 876 |
| 2000 | 806 |
| 1999 | 936 |
| 1998 | 1,028 |
| 1997 | 698 |
| 1996 | 694 |
| 1995 | 1,040 |
| 1994 | 746 |
| 1993 | 804 |
| 1992 | 512 |
| 1991 | 1,101 |
| 1990 | 762 |
| 1989 | 737 |
| 1988 | 1,160 |
| 1987 | 1,059 |
| 1986 | 859 |
| 1985 | 743 |
| 1984 | 839 |
| 1983 | 1,081 |
| 1982 | 723 |
| 1981 | 733 |
| 1980 | 954 |
| 1979 | 739 |
| 1978 | 858 |
| 1977 | 925 |
| 1976 | 703 |
| 1975 | 845 |
| 1974 | 673 |
| 1973 | 907 |
| 1972 | 722 |
| 1971 | 857 |
| 1970 | 876 |
| 1969 | 744 |
| 1968 | 797 |
| 1967 | 560 |
| 1966 | 773 |
| 1965 | 763 |
| 1964 | 881 |
| 1963 | 824 |
| 1962 | 794 |
| 1961 | 761 |
| 1960 | 773 |
| 1959 | 1,028 |
| 1958 | 666 |
| 1957 | 802 |
| 1956 | 836 |
| 1955 | 1,059 |
| 1954 | 961 |
| 1953 | 986 |
| 1952 | 925 |
| 1951 | 616 |
| 1950 | 613 |
| 1949 | 961 |
| 1948 | 810 |
| 1947 | 925 |
| 1946 | 736 |
| 1945 | 609 |
| 1944 | 993 |
| 1943 | 901 |
| 1942 | 779 |
| 1941 | 975 |
| 1940 | 828 |
| 1939 | 973 |
| 1938 | 883 |
| 1937 | 871 |
| 1936 | 1,223 |
| 1935 | 813 |
| 1934 | 1,179 |
| 1933 | 1,100 |
| 1932 | 889 |
| 1931 | 1,066 |
| 1930 | 925 |
| 1929 | 642 |
| 1928 | 686 |
| 1927 | 616 |
| 1926 | 723 |
| 1925 | 923 |
| 1924 | 532 |
| 1923 | 819 |
| 1922 | 927 |
| 1921 | 1,172 |
| 1920 | 765 |
| 1919 | 987 |
| 1918 | 838 |
| 1917 | 568 |
| 1916 | 926 |
| 1915 | 480 |
| 1914 | 957 |
| 1913 | 931 |
| 1912 | 709 |
| 1911 | 988 |
| 1910 | 778 |
| 1909 | 726 |
| 1908 | 803 |
| 1907 | 611 |
| 1906 | 856 |
| 1905 | 757 |
| 1904 | 574 |
| 1903 | 628 |
| 1902 | 647 |
| 1901 | 1,051 |
| 1900 | 1,007 |
| 1899 | 902 |
| 1898 | 882 |
| 1897 | 889 |
| 1896 | 889 |
| 1895 | 920 |