Average Temperatures for Illinois in May





Average temperatures for May at cities throughout Illinois are listed below.

You can jump to a separate table for each region of the state: Chicago Area, Northern Illinois, Central Illinois and Southern Illinois.

The tables give the normal maximum and minimum temperatures based on weather data collected from 1991 to 2020 by the US National Centers for Environmental Information.

Chicago Area

Average May temperatures
High °F Low °F Place High °C Low °C
71 50 Aurora 22 10
68 48 Chicago Botanical Garden 20 9
72 52 Chicago Midway Airport 22 11
71 51 Chicago O'Hare Airport 21 10
70 48 Elgin 21 9
71 49 Joliet 22 10
70 48 Rochelle 21 9

Northern Illinois

Average temperatures in May
High °F Low °F Place High °C Low °C
68 48 Antioch 20 9
70 49 DeKalb 21 10
71 51 Dixon 22 10
70 48 Freeport 21 9
74 51 Moline 23 11
71 50 Rockford 22 10
67 46 Waukegan 19 8

Central Illinois

Normal temperatures for May
High °F Low °F Place High °C Low °C
75 56 Alton 24 13
72 50 Bloomington 22 10
77 57 Cahokia 25 14
74 53 Champaign 23 12
77 54 Charleston 25 12
75 52 Danville 24 11
74 54 Decatur 23 12
73 51 Kankakee 23 11
72 51 Ottawa 22 11
74 53 Peoria 23 12
73 54 Quincy 23 12
76 54 Springfield 24 12

Southern Illinois

Average May temperature
High °F Low °F Place High °C Low °C
79 56 Belleville 26 14
78 58 Cairo 26 14
77 55 Carbondale 25 13
74 55 Mt Vernon 23 13
Reference

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

Illinois Temperatures
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