FindMyMarathon / Race-day weather
Chicago Marathon Weather Forecast 2026 IS LIVE!
Check the Chicago Marathon weather for your time on the course.
Choose your start wave and goal finish time for temperature, rain chance and wind. Free to use.
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Your race forecast
Goal 2:00:00 Chicago local time
Start
7:35am- Wind
- 1 mph NE
- Gusts
- 7 mph
- Humidity
- 81%
- Dewpoint
- 53°F
- Rain chance
- 0%
Halfway
8:35am- Wind
- 4 mph E
- Gusts
- 7 mph
- Humidity
- 77%
- Dewpoint
- 53°F
- Rain chance
- 0%
Finish
9:35am- Wind
- 5 mph SSE
- Gusts
- 9 mph
- Humidity
- 72%
- Dewpoint
- 55°F
- Rain chance
- 0%
Checkpoint colorsStartHalfwayFinish
Expect a partly cloudy start on Grant Park near 58°F, with temperatures rising to about 64°F by the finish. Partly cloudy conditions should hold for much of the day. The biggest wind challenge looks to be in miles 16 through 20, where headwind exposure may be the most noticeable. Humidity may become more noticeable in the second half and late race, especially if you are pressing after halfway.
Temperature & rain during your race
Miles 14–19 include an illustrative west-side warming adjustment (peaking at +3°F); this is not a measured neighborhood forecast. Start, halfway and finish forecast values are unchanged.
Wind along the course
Start to Mile 5
Neutral
- Tailwind
- 5%
- Headwind
- 51%
- Gusts
- 7 mph
Miles 6 - 10
Neutral
- Tailwind
- 5%
- Headwind
- 89%
- Gusts
- 7 mph
Miles 11 - 15
Neutral
- Tailwind
- 5%
- Headwind
- 57%
- Gusts
- 7 mph
Miles 16 - 20
Challenging
- Tailwind
- 0%
- Headwind
- 42%
- Gusts
- 7 mph
Miles 21 to Finish
Neutral
- Tailwind
- 0%
- Headwind
- 5%
- Gusts
- 9 mph
What to expect
- The opening miles should feel fairly comfortable for marathon running, with a good chance to settle into pace early.
- The final 10K could feel more taxing than the early miles as temperatures or humidity build from halfway back toward the finish.
- A meaningful headwind setup could matter on exposed stretches, especially after halfway and through the second half when small pace changes become more costly.
- On the western portion of the course (approximately miles 14–19), runners may experience temperatures around 3–5°F warmer than lake-influenced sections. Greater distance from Lake Michigan, limited tree shade, and heat retained by pavement can contribute to this difference. The graph illustrates a possible 3°F midsection increase; it is an estimate, not a separate measured forecast.
What to wear & carry
Based on the start temperature, wind and rain risk.
- Race kit should be enough at the start
- Prioritize fluids late
- No major rain gear needed
- Minimal extra gear needed
2026 vs. typical Chicago
Historical race-day comparison
| Conditions | 2026 forecast | Typical | Difference |
|---|---|---|---|
| Race average temp | 61°F | 58°F | +3° |
| Start temperature | 58°F | 52°F | +6° |
| Start humidity | 81% | 77% | +4% |
| Start wind speed | 1 mph | 7 mph | -6 mph |
| Start wind direction | NE | N | — |
| Start conditions | Partly Cloudy | Mostly Cloudy | Different |
