Compare marathon courses
Two races, one table. Climbing, net drop, the BQ downhill adjustment, and five years of observed race-morning weather — the numbers that actually separate courses.
The read
- Chicago Marathon climbs 476 ft less than California International Marathon (CIM). Total climbing is the course factor physiology says costs you the most, so this is the single biggest difference between the two courses.
- California International Marathon (CIM) averages 8°F cooler on race morning. Heat slows marathoners more than hills do, so this can outweigh a climbing gap.
| California International Marathon (CIM) | Chicago Marathon | |
|---|---|---|
| Next edition | Dec 6, 2026 | Oct 10, 2027 |
| Location | Sacramento, California | Chicago, Illinois |
| Course character | Net downhill · point-to-point | Flat · fast · loop |
| Total climbing | 663 ft | 187 ft |
| Net elevation change | 366 ft downest. | 10 ft upest. |
| Steepest grade | — | — |
| BQ adjustment | None | None |
| Course speed | Fast | Very fast |
| Avg race-morning temp | 46°F (5-yr avg) | 54°F (5-yr avg) |
| Avg dew point | 44°F (5-yr avg) | 48°F (5-yr avg) |
| Warmest observed morning | 53°F in 2023 | 69°F in 2021 |
| USATF certification | CA18004DT | — |
Where the numbers come from
Climbing and net drop come from each course's elevation data. Figures marked est. are our estimates rather than official race data — fine for describing a course, not for splitting hairs between two close ones.
Race-morning weather is observed conditions from each race's recent editions (7–11am at the start line), not climate averages: Open-Meteo historical reanalysis (ERA5), 7-11am local at the start line.
The BQ adjustment is the B.A.A.'s net-downhill rule for the 2027 Boston Marathon: +5:00 for 1,500–2,999 ft of net drop, +10:00 for 3,000–5,999 ft, and courses at 6,000 ft or more cannot be used to qualify.