What's the weather like in Chicago in September?Located in the United States’ Midwest along the shores of Lake Michigan, the city of Chicago has a humid continental climate. This brings hot summers, cold winters, and mild springtime and autumn months to the region. September is the start of autumn in Chicago, with warm and sometimes mild temperatures in the daytime, and cooler evenings after the sun sets. If you want to avoid the crowds of summer, September is a great time of year to visit this vibrant city.
AveragesOn average, the daytime temperature reaches a warm 24°C in September, with chilly lows of 12°C. The days are getting shorter at this time of year, but with around 13 hours of daylight at the start of the month there’s still plenty of time to explore the city’s many sights. On average, Chicago has 90mm of rain in September, so although you may see some showers the wet weather won’t ruin your holiday.