Monthly weather forecast and Climate
Chicago, IL US

Warmest month (with highest average high temperature) is July (84.2°F).
Month with lowest average high temperature is January (31.5°F).

Month with highest average low temperature is July (67.5°F).
Coldest month (with lowest average low temperature) is January (18.2°F).

Month with highest relative humidity is December (75.5%).
Month with lowest relative humidity is May (64.1%).

Wettest months (with highest rainfall) are May and June (4.1").
Driest month (with lowest rainfall) is February (1.9").

Month with highest number of rainy days is May (11.4 days).
Month with lowest number of rainy days is September (8.2 days).

Month with highest snowfall is January (11.5").
Months with lowest snowfall are May, June, July, August and September (0").

Month with highest number of snowfall days is January (8.1 days).
Months with lowest number of snowfall days are May, June, July, August and September (0 days).

Best month for swimming (with highest average sea temperature) is August (70°F).
Coldest months (with lowest average sea temperature) are February, March and April (37°F).

Months with longest days are May, June and July (Average daylight: 15).
Month with shortest days is December (Average daylight: 9).

Month with most sunshine is June (Average sunshine: 10.4).
Month with least sunshine is December (Average sunshine: 3.4).

Months with highest UV index are June and July (UV index 9).
Months with lowest UV index are January and December (UV index 1).