FindMyMarathon / Race-day weather
Chicago Marathon Weather Forecast 2026 IS LIVE ON 9/28!
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.
Your race details
Choose your start wave and finish goal first. These selections personalize your forecast, wind estimates and race advice.
Your selections will be remembered on this device.
Your race forecast
Goal 2:00:00 Chicago local time
Start
7:35am- Wind
- 10 mph S
- Gusts
- 25 mph
- Humidity
- 47%
- Dewpoint
- 26°F
- Rain chance
- 6%
Halfway
8:35am- Wind
- 11 mph S
- Gusts
- 25 mph
- Humidity
- 43%
- Dewpoint
- 25°F
- Rain chance
- 6%
Finish
9:35am- Wind
- 13 mph S
- Gusts
- 25 mph
- Humidity
- 38%
- Dewpoint
- 24°F
- Rain chance
- 6%
Checkpoint colorsStartHalfwayFinish
Expect a overcast start on Grant Park near 46°F, with temperatures staying fairly steady through the route. Overcast conditions should hold for much of the day. Wind impact looks mixed rather than strongly favorable or strongly difficult over the full course. Overall, the temperature setup looks fairly manageable for steady pacing. Gusts could make exposed sections feel more variable than the steady wind speed suggests.
Temperature & rain during your race
5 points · 30-minute estimates
Wind along the course
Exposure by course section
Start to Mile 5
Helpful
- Tailwind
- 20%
- Headwind
- 0%
- Gusts
- 25 mph
Miles 6 - 10
Neutral
- Tailwind
- 1%
- Headwind
- 0%
- Gusts
- 25 mph
Miles 11 - 15
Neutral
- Tailwind
- 7%
- Headwind
- 0%
- Gusts
- 25 mph
Miles 16 - 20
Slightly helpful
- Tailwind
- 16%
- Headwind
- 1%
- Gusts
- 25 mph
Miles 21 to Finish
Neutral
- Tailwind
- 0%
- Headwind
- 2%
- Gusts
- 25 mph
What to expect
- The opening miles should feel fairly comfortable for marathon running, with a good chance to settle into pace early.
- Late-race conditions look relatively manageable, which should reward runners who stay patient through Halfway and the second half.
- Wind impact looks mixed rather than strongly favorable or strongly challenging across the full route.
- Stronger gusts may make some open boulevards or exposed sections feel more variable than the steady wind numbers suggest.
What to wear & carry
Based on the start temperature, wind and rain risk.
- Race kit should be enough at the start
- Normal fluid plan likely fine
- No major rain gear needed
- Light gloves optional if you run cold
2026 vs. typical Chicago
Historical race-day comparison
| Conditions | 2026 forecast | Typical | Difference |
|---|---|---|---|
| Race average temp | 46°F | 58°F | -12° |
| Start temperature | 46°F | 51°F | -5° |
| Start humidity | 47% | 77% | -30% |
| Start wind speed | 10 mph | 8 mph | +2 mph |
| Start wind direction | S | WNW | — |
| Start conditions | Overcast | Mostly Cloudy | Different |