Forecast for each day of Chicago Marathon 2026
- SunOct 11
Not in the forecast yet. The National Weather Service forecasts about 7 days ahead, so this day comes into range around Oct 4.
Each day covers only the event’s hours, in local time. Levels use the same weather-risk scale as the Road Travel app. For delays or closures, follow the event’s own announcements.
What October is usually like
Monthly normals from NOAA’s Chicago Northerly Island station, the nearest long-term station to Grant Park (2 miles away).
| Month | Chicago Chicago Northerly Island station · 2 mi from Grant Park |
|---|---|
| High / low °F | |
| Jan | 32° / 20° |
| Feb | 36° / 23° |
| Mar | 45° / 31° |
| Apr | 55° / 40° |
| May | 66° / 50° |
| Jun | 76° / 60° |
| Jul | 81° / 67° |
| Aug | 80° / 67° |
| Sep | 73° / 60° |
| Oct | 61° / 48° |
| Nov | 49° / 36° |
| Dec | 37° / 25° |
NOAA NCEI U.S. Climate Normals, 1991–2020: CHICAGO NORTHERLY IS (USC00111550, 583 ft). Precipitation is the monthly total of rain and melted snow, in inches. “—” means the station does not publish that normal.
Official updates
Delays, closures and safety instructions come from the organizers, so these go straight to their pages and to the National Weather Service.
- Chicago Marathon · officialChicago Marathon race-day schedule
- Chicago Marathon · officialChicago Marathon rules, safety and Event Alert System
- Chicago Marathon · officialChicago Marathon official site
- National Weather ServiceForecast for Grant Park
Check the official National Weather Service forecast for Grant Park and the organizers’ announcements before you go.
Driving to Chicago Marathon? See the weather for the hour you’ll be on the road
Road Travel times the forecast to your drive into Chicago, so you see conditions where you will be when you get there, and alerts about storms ahead on the way.
Questions about Chicago Marathon weather
When is Chicago Marathon 2026?
October 11, 2026, at Grant Park in Chicago. Race day: 5:30 AM–4 PM, per the organizers.
How warm is it in Chicago in October?
October averages a high of 61°F and a low of 48°F at NOAA’s Chicago Northerly Island station (1991–2020 normals).