Weather By Day

September Chicago Weather 
September Chicago Weather
Record High: 99°F
Normal High: 74°F
Normal Low: 54°F
Record Low: 28°F
Avg Monthly Rain: 3.27"
Rec 1 Day Rain: 2.88"

Chicago Weather In September

Chicago Weather In September sees a drop in temperature and humidity from the prior couple of months, and that can be a good thing unless you encounter and unusually cool day towards the end of the month. Some temperatures below freezing have been recorded in Chicago in September, but no snow. The weather in Chicago in September is actually quite pleasant most of the time.