Fox Valley Marathon
St. Charles, United States of America · Sunday 20 September 2026
Fox Valley Marathon, held on September 21, 2025, in St. Charles, Illinois, is a flat and fast event that takes runners through the scenic towns along the Fox River. The course includes towns, bridges, waterfalls, parks, river paths, and even an authentic Dutch windmill, providing a mix of urban charm and natural beauty. With its well-shaded route, runners can enjoy a cooler environment during the race.
Difficulty Calculator
h
:m
:s
Adjusted Time
4:06:34
Time difference: +6.6 minutes compared to a flat, road, temperate course.
Course Details
Elevation Gain0m
Elevation High223m
Elevation Low192m
Weather Forecast
High32°C
Low18°C
Chance of Rain60%
How hard is Fox Valley Marathon?
Difficultharder than 66% of marathons
Flattest / easiestHardest
On our difficulty model, Fox Valley Marathon plays about 10 minutes slower than an average road marathon for a 3:30 runner. It ranks #394 hardest of 1150 marathons we analyse, and #198 of 575 in United States of America. Use the calculator above to see the exact adjusted time for your own goal pace.
What will you run at Fox Valley Marathon?
Estimated finish times on this course versus the same effort on an average road marathon, based on its elevation, surface, and expected race-day temperature.
| Average-course time | On Fox Valley Marathon | Difference |
|---|---|---|
| 3:00:00 | 3:03:16 | +03:16 |
| 3:30:00 | 3:34:53 | +04:53 |
| 4:00:00 | 4:06:34 | +06:34 |
| 4:30:00 | 4:38:18 | +08:18 |
| 5:00:00 | 5:10:05 | +10:05 |
| 5:30:00 | 5:41:56 | +11:56 |
| 6:00:00 | 6:13:50 | +13:50 |
Use the calculator above for your exact goal time. Want a prediction from your own training? Try the marathon time predictor.
Fox Valley Marathon 2026 Course Analysis
Fox Valley Marathon is a full marathon held in St. Charles, United States of America. It is scheduled for Sunday 20 September 2026. The course is run on road surface with 0m of total climbing, with its high point near 223m above sea level. For registration and full race details, visit the official Fox Valley Marathon website.
Elevation Profile
This is a very flat course, with only 0m of total climbing and little change in altitude throughout. Flat profiles let you hold an even pace from start to finish, which makes this a fast, PB-friendly race.
Expected Race Day Weather
Based on historical weather data for September, the expected race day conditions are as follows. Hot conditions are expected, with temperatures between 18°C and 32°C. Heat is one of the biggest performance factors in distance running - for every degree above 15°C, finish times can slow by roughly 1-2%. Extra hydration and a conservative start are strongly recommended. There is a high chance of rain (60%). Runners should prepare for wet conditions, including appropriate footwear and clothing choices.
Surface Type: Road
Fox Valley Marathon is run on road surfaces, which provide the fastest and most predictable conditions for racing. Road courses allow for consistent pacing and are typically the best choice for a personal best.
Looking for an easier marathon or a tougher challenge? You can also compare Fox Valley Marathon against other marathons to find the right race for your goals.
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If Fox Valley Marathon fits your goal, these courses play out about the same on our difficulty model.
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