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What is the Weather in Chicago in September

Updated: May 10, 2024

This post is an overview of the September weather in Chicago, including snow and precipitation forecasts, as well as tips on how to dress and things to do.

If you'll be in town either before or after the month, make sure to check our posts on weather in August and October.


This month turns out to be a very pleasant month as far as temperatures, with less rainy days than in August.

The long summer days are behind us now. Often the thermometer will reach over 60 °F (16 °C) in Chicago, with an average high of 75 °F (24 °C) and low of 54 °F (12 °C).

Average Temperatures in Chicago in September


In September, the city experiences less wind and less rain!

There is a steep decline in stormy weather after the summer thunderstorms of August, and rainfall only adds up to 3.2 inches (82 mm) of rain over the course of about 8 rainy days.

The sun shines for an average of 12 hours and 27 minutes a day, with about 9 clear days throughout the month.

The average humidity during August is 71%, with the mornings reaching up to 85% humidity, and letting up throughout the day to around 55%

How much Sun in Chicago in September


Chicago in September can be a little unpredictable, and you will want to reflect that in your wardrobe.

Be sure to still pack comfortable, light-weight clothing for the warmer days and hours of this month, especially in the early days of September.

The temperatures begin to cool during the evening hours, as well as later in the month, so you will want to be prepared with layers.

What to wear in September in Chicago

Sunblock and comfortable walking shoes are still essential this month, as there are many great outdoor activities and beautiful parts of the city to explore with our walking tours.

Throw a water bottle in as well, so you can stay hydrated during your Chicago adventure.


Below are the top things to do in September in Chicago.

But, be sure to read our full post on what to do in Chicago in September which includes free things to do, night and family-friendly activities and attractions, as well as our definitive post on the best things to do in Chicago.

And if you are planning on visiting many of Chicago's top attractions, then you should consider a tourist concession pass as you could save up to 50% of retail ticket prices to tours, attractions, and restaurants.

Be sure to check out all the top things to do in  September in our main post.

Seasonal Outlook

July to September 2024 Chicago

There is a 75% chance for normal to above normal temperatures with near normal rainfall.

Fred Pickhardt
Ocean Weather Services

About The Author

Fred Pickhardt

Fred is a marine meteorologist and sailed briefly with American Export Lines in the Far East trade. He has extensive experience in weather analysis, weather forecasting, and forensic weather event reconstructions. Fred founded Ocean Weather Services and currently provides forensic marine weather reports to the maritime industry.
Updated: May 10th, 2024
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