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Illinois Weather Records

Weather averages and records for the U.S. state of Illinois based on data made available by the NOAA.
Illinois Statewide Averages
Average temperatures over the entire territory of the state, from 1991–2020.
Month High (°F) Low (°F)
January 34.7 18.6
February 39.7 22.4
March 51.3 31.5
April 63.9 41.3
May 74.1 52.4
June 82.9 61.5
July 85.8 65.1
August 84.4 62.8
September 78.5 55.0
October 66.1 43.5
November 51.3 33.0
December 39.4 23.7
Entire Year 62.8 42.7
Illinois Cities
Yearly weather averages for various places in Illinois, from 1991–2020.
City Average (°F) Record (°F) Yearly (inches)
High Low High Low Precipitation Snow
Aledo 59.8 39.3 113 -33 36.5 21.3
Aurora 60.0 40.2 111 -26 39.1 31.2
Belleville 68.7 46.7 110 -27 42.9 11.6
Bloomington-Normal 62.0 40.4 114 -24 38.9 20.9
Carbondale 66.9 45.2 113 -25 48.4 11.3
Carlyle 65.0 45.3 113 -22 44.5 n/a
Champaign 62.3 42.6 109 -25 40.7 20.7
Charleston 64.8 44.8 110 -27 43.6 20.6
Chicago 60.2 44.0 106 -25 40.9 39.4
Danville 63.1 43.1 112 -26 42.4 13.0
Decatur 63.6 44.2 113 -25 39.8 14.7
Dixon 59.1 39.6 110 -32 40.2 34.1
Du Quoin 66.8 46.5 113 -22 46.9 11.0
Elgin 58.9 39.2 103 -27 39.3 31.7
Elizabeth 58.1 36.1 103 -35 39.2 33.8
Fairfield 66.6 45.2 113 -23 45.5 13.6
Freeport 58.0 38.0 112 -31 38.3 32.8
Galesburg 60.2 41.6 112 -28 38.8 23.6
Geneseo 60.6 41.7 107 -25 38.9 27.9
Hoopeston 62.2 42.8 111 -25 40.5 17.8
Jacksonville 64.0 41.3 114 -28 39.0 18.4
Joliet 60.0 41.2 104 -26 37.0 16.7
Kankakee 61.5 41.2 109 -29 37.8 20.5
Kewanee 59.2 39.0 105 -27 39.0 30.0
Lincoln 62.8 41.4 113 -34 39.0 19.3
Moline 61.2 41.0 104 -33 38.3 36.1
Monmouth 62.0 41.2 110 -27 38.8 25.1
Morris 60.7 41.5 109 -26 39.0 25.9
Morrison 60.3 38.2 112 -35 39.1 32.2
Mt. Vernon 64.2 44.7 114 -22 45.0 11.3
Olney 65.3 44.5 112 -25 47.8 11.6
Ottawa 61.1 40.9 112 -26 35.1 22.5
Pana 64.9 43.6 115 -25 42.7 15.8
Paris 62.5 43.0 109 -23 42.5 18.8
Peoria 61.9 42.9 105 -25 37.5 26.0
Quincy 62.6 43.7 114 -29 36.2 n/a
Rantoul 63.3 41.2 109 -27 39.4 10.9
Rockford 59.0 39.5 112 -31 37.2 38.0
Springfield 63.7 43.7 112 -24 38.0 21.6
Tuscola 63.1 43.2 113 -26 40.9 18.0