Racing
Chicago Marathon Weather Guide
Weather expectations and preparation for the Chicago Marathon.
Run Window TeamApril 19, 20261 min read
Chicago Marathon weather is October in the Midwest—often ideal, sometimes challenging.
Chicago October Weather
What's typical:
- Morning start: 45-55°F
- Warming through race
- Low humidity usually
- Occasional warm years
Historical Patterns
Most years: Good to excellent conditions for fast times.
Occasional warm years: Can reach 70s, affects pacing.
2007: Extreme heat (88°F) forced race cancellation for slowest runners.
Race Day Specifics
Early start:
- 7:30am start
- Can be cool at start
- Warms as you run
Lake effect: Wind off Lake Michigan can be factor.
Preparation Strategies
Train for:
- Cool morning start
- Warming conditions
- Some heat preparation (just in case)
Chicago-Specific Gear
Bring:
- Throwaway layers for start
- Light gloves (morning)
- Sunglasses (often sunny)
Chicago usually delivers good marathon weather. Be ready for warming conditions through the race.
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