01 · Historical band
9–17°C, with a 25% historical rain signal
This is planning context, not a forecast. Use it to pack options rather than choose one fixed race kit.
Chicago Marathon · October 2026
Weather & climate
Major weekend operating notes
02 · Start wait
Dress for standing still
The day begins at Start. Bring a removable layer that works before the gun without becoming dead weight on course.
03 · Decision point
Switch inside seven days
Once the live forecast is available, prioritize hourly temperature, wind, rain timing, and the feels-like value at your wave.
Typical race-week temperatures run 9–17°C with about a 25% chance of rain on any given day. Dress for the start-line wait, not the finish — you'll warm up fast once the gun goes.
Race-week forecast window
Checking the race-week forecast window…
Forecast loads live; the climate normals above are baked in and don't change.