Average Rainfall for Illinois in August





The tables below give monthly averages for rainfall during August 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 rainfall 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 August
Days Place Inches Milli­metres
10 Aurora 4.1 103
10 Chicago Botanical Garden 4.8 121
9 Chicago Midway Airport 4.0 101
10 Chicago O'Hare Airport 4.9 124
9 Chicago University 3.8 97
10 Elgin 4.8 122
9 Joliet 4.2 106

Northern Illinois

August averages for total rainfall
Days Place Inches Milli­metres
10 Antioch 4.1 104
9 DeKalb 4.4 111
8 Dixon 4.5 114
10 Freeport 4.3 109
10 Moline 4.5 115
10 Rockford 4.6 117
Waukegan 3.8 97

Central Illinois

Average amount of rain in August
Days Place Inches Milli­metres
7 Alton 3.2 80
8 Cahokia 3.4 86
9 Danville 3.5 88
9 Peoria 3.2 82
9 Quincy 3.6 92
8 Springfield 3.2 82
9 Urbana 3.9 100

Southern Illinois

Precipitation totals for August
Days Place Inches Milli­metres
7 Cairo 3.0 76
7 Marion 2.9 73
8 Mt Vernon 3.0 75
Reference

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

Illinois Precipitation
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