Illinois, Climate Division 5. East, Average Temperature Rankings, May 2020 1901-2000 Degrees Fahrenheit 1 59.5 61.0 -1.5 43 86 1907 2018 2008 2019 bottom-third 1994 2 53.8 55.5 -1.7 26 103 1907 1977 1997 2019 bottom-third 3 50.0 49.7 0.3 68 61 1960 2012 2019 2018 normal 1933,1968 4 45.1 44.2 0.9 84 45 1978 2012 2019 2018 normal 1903,1952,2022 5 42.3 40.1 2.2 108 21 1978 2012 2019 2017 top-third 1933,1953,1955,1973,1976,2002 6 40.9 38.1 2.8 113 15 1904,1978 2012 2019 2017 top-third 7 40.1 38.3 1.8 100 28 1904 2012 2019 2017 top-third 8 41.8 40.2 1.6 101 27 1904 2012 2019 2017 top-third 1949,1972,1974 9 44.9 43.0 1.9 108 20 1904 2012 2019 2017 top-third 1995 10 47.6 45.9 1.7 107 21 1904 2012 2019 2017 top-third 2005 11 50.2 48.5 1.7 108 20 1904 2012 2019 2017 top-third 12 51.9 50.3 1.6 109 19 1904 2012 2019 2017 top-third 18 47.5 46.2 1.3 99 28 1905 2017 2019 2018 top-third 1935,1953,2002 24 51.5 50.3 1.2 104 23 1905 2017 2019 2018 top-third 1956,1987,2001,2008 36 51.4 50.3 1.1 98 28 1905,1906 2018 2016 2019 top-third 1935,1957,1988 48 52.2 50.3 1.9 123 2 1905 2019 2018 2019 top-tenth 2018 60 52.5 50.3 2.2 123 1 1905,1906,1908 2020 2019 2020 highest