The 2026 Fox Valley 20M has concluded.
The 2026 Fox Valley Marathon Races have been cancelled due to extended setup delays caused by incidents of lightning. Packet and finisher medal pickup is staged in the downtown St. Charles parking garage beginning at 7:00 AM. All registrants are considered finishers for Endurance Medal streaks.

Fox Valley 20M

Race complete
St. Charles, IL, USA · September 20, 2026·
rain67°·67° high·Breezy·Light rain
5
Register

Race Day Weather

rain
67°at start
68° high
Breezy
Rain likely
Your goal
0:00:00

Warm start, moderate wind, rain likely, high humidity

Starting at 67°F, heat will be a factor from the gun — go out conservative and stay on top of hydration. Moderate winds around 14mph may affect pacing on open sections of the course. Rain is likely — waterproof your phone and bib, and consider a disposable poncho for the corral. High humidity (95%) will make it harder to cool down through sweat — increase fluid intake accordingly.

rain4
cloudy4
rain5
partly-cloudy-day5
rain5
cloudy5
rain5
rain5
rain5
rain5
rain5

Pace Calculator

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We'll text or email you when the forecast shifts — so you can adjust gear, pacing, and strategy. Max one per day.

Race Plan

Get your personalized Fox Valley 20M race plan

A mile-by-mile breakdown of where your time goes, weather-adjusted splits, fueling timeline with aid stations, packing checklist, carb tracker, spectator guide, all built around your goal and race-day conditions.

Race Pace
Weather Splits
Nutrition
Gear & Packing
T-Minus
Carb Tracker
Spectator Guide
Race Band

Race Info

The Fall Final 20 is a 20-mile race that starts and finishes at Mt. St. Mary Park in St. Charles. It follows the Fox River south through Geneva and Batavia to a turnaround near North Aurora, then returns along the opposite bank on town streets and river paths. The course is gentle and shaded, with a small roller near mile 10, and it is used by many runners as a long training run before a fall marathon.

Race weekend

Sunday, September 20
7:00 AMMarathon (26.2 mi)7:00 AMHalf Marathon (13.1 mi)
7:00 AM20M (20.0 mi)
7:10 AM5K (3.1 mi)
Area Map

Course Map

FAQ

When is the 2026 Fox Valley 20M?

The 2026 Fox Valley 20M will be held on Sunday September 20, 2026.

What will the weather be like for the 2026 Fox Valley 20M?

The forecast calls for a high of 69°F and a low of 61°F with a 100% chance of rain.

Historical Weather

Based on 16 years of data
Avg Temp
65°F
L:59° H:70°
RunScore
6
Conditions
Rain Freq
31%
5 of 16 yrs
Wind7mph
Dew58°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScoreResults
2026
rain
65°/67°Light
5
2025
partly-cloudy-day
66°/73°-
4
2024
partly-cloudy-day
69°/71°Light
4
2023
rain
59°/62°Light
6
2022
cloudy
69°/78°-
4
2021
clear-day
59°/80°-
4
2019
cloudy
72°/78°Light
3
2018
clear-day
65°/81°-
3
2017
partly-cloudy-day
67°/81°-
4
2016
clear-day
55°/72°-
6
2015
clear-day
48°/66°-
8
2014
clear-day
55°/61°-
8
2013
clear-day
43°/63°-
8
2012
clear-day
47°/70°-
7
2011
cloudy
54°/56°Light
8
2010
partly-cloudy-day
53°/65°-
8