Average Precipitation for Illinois in May





The tables below give monthly averages for rainfall plus snowfall during May at cities in Illinois.

Each place has a total for the amount of precipitation it usually receives this month. Most sites also have information on the number of days with wet weather. This includes the days when precipitation amounts to 0.01 inches (0.25 millimetres) or more.

The precipitation totals are averages based on weather data collected from 1981 to 2010 for the NOAA National Climatic Data Center.

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

Chicago Area

Average monthly precipitation in May
Days Place Inches Milli­metres
12 Aurora 4.0 102
12 Chicago Botanical Garden 4.0 102
11 Chicago Midway Airport 4.1 105
12 Chicago O'Hare Airport 3.7 93
11 Chicago University 4.1 103
12 Elgin 4.2 107
11 Joliet 4.1 104

Northern Illinois

May averages for total rainfall plus snowfall
Days Place Inches Milli­metres
12 Antioch 4.2 108
12 DeKalb 4.6 116
10 Dixon 4.4 112
12 Freeport 4.0 101
12 Moline 4.3 110
12 Rockford 4.0 102
Waukegan 4.0 102

Central Illinois

Average amount of rain and snow in May
Days Place Inches Milli­metres
11 Alton 5.1 130
12 Cahokia 4.7 118
12 Danville 4.7 120
12 Peoria 4.3 110
12 Quincy 4.5 115
12 Springfield 4.2 108
12 Urbana 4.9 124

Southern Illinois

Precipitation totals for May
Days Place Inches Milli­metres
11 Cairo 5.3 134
11 Marion 6.0 151
13 Mt Vernon 5.2 131
Reference

National Climatic Data Center. NOAA's 1981-2010 Climate Normals.

Illinois Precipitation
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