Chicago, Illinois Weather in October

Cool days by the lake

October feels like proper autumn in Chicago. Days are cool, nights are chilly, and rain can interrupt a walk. The average high is 16°C, with rain on 11 days. You'll still get some sun, but shorter daylight means less time for outdoor plans.

The weather suits the Art Institute, the Field Museum and walks through Millennium Park. You can also stroll the Lakefront Trail, but lake winds can make it feel colder than downtown. Save long outdoor days for dry spells, and don't count on a beach visit feeling warm.

Fall events and Halloween

The Chicago Marathon brings runners and spectators to the city in October. Open House Chicago also gives visitors a chance to explore buildings that are usually closed to the public. Around Halloween, you'll see seasonal events and decorations across the city.

Families who enjoy spooky stories can look for Halloween events around Lincoln Park, but check details for the year you're visiting. Marathon weekend is lively, though road closures can make getting around downtown slower.

Fewer summer crowds

Crowds and hotel prices generally ease after the busy summer months. October can be a good choice if you want to visit major sights without peak-season crowds. The marathon and popular fall events can bring busy weekends, so prices and rooms may vary.

One Chicago-specific tip: on marathon weekend, check the route before heading across downtown. The course closes streets, so the CTA "L" train is often a simpler way to reach places like the Loop and Millennium Park. At the end of a cool day, warm up with deep-dish pizza in River North or another neighborhood you're exploring.