Historical Weather in Illinois
See 55+ years of weather history for any date in Illinois going back to 1970.
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Monthly Climate Averages
Historical temperature and precipitation averages for Chicago, IL, based on 55+ years of weather data.
Warmest MonthJulyAvg High: 81°F / Low: 68°F
Coldest MonthJanuaryAvg High: 33°F / Low: 21°F
Jan
33°/ 21°
💧 0.1"
Feb
36°/ 23°
💧 0.1"
Mar
46°/ 33°
💧 0.3"
Apr
56°/ 41°
💧 0.4"
May
66°/ 51°
💧 0.3"
Jun
77°/ 62°
💧 0.4"
Jul
81°/ 68°
💧 0.3"
Aug
80°/ 68°
💧 0.5"
Sep
74°/ 61°
💧 0.3"
Oct
63°/ 50°
💧 0.6"
Nov
50°/ 38°
Dec
38°/ 27°
Temperatures in Fahrenheit. Precipitation and snowfall in inches.
Climate data based on Chicago, the largest city in Illinois.
Illinois All-Time Temperature RecordsSee the hottest and coldest days ever recorded since 1970
→Illinois All-Time Weather ExtremesRain, snow, and temperature extremes for any Illinois city or ZIP code
→Major Cities in Illinois
Today's Weather History in Illinois
See how today compares to 55+ years of weather data for Illinois cities.