18th Annual F^3 Lake Half Marathon & 5k
Decision scores
Six 0–100 scores telling you, at a glance, who this race is for.
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About the Race
The 18th Annual F^3 Lake Half Marathon & 5k is Chicago's Original Winter Half Marathon. Each year, thousands of runners flock to this community-built event, gathering in the warmth of Soldier Field's United Club before tackling wind & weather along a lakefront course that features splits every 5km. A must for anyone preparing for a spring marathon or just resolving to stay fit throughout the new year. F^3 sold out in 2016-2020 and 2023-present. Every registrant will once again receive one of ...
Course Profile
Course profile data unavailable for this race.
Course features
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History & past results
Past finisher times and year-over-year participation will appear here once the organizer publishes them.
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Common questions
How hard is the 18th Annual F^3 Lake Half Marathon & 5k Half Marathon?
We don't have a verified elevation profile yet — check the organizer's course map for the climb breakdown.
What should I wear?
Dress for ~10°F warmer than the standing temperature once you start running. Throwaway long-sleeve at the start, gloves and a hat for sub-50°F mornings, singlet plus visor when it climbs above 60°F. The race-day forecast above is the source of truth closer to the date.
When does it sell out?
No published deadline. Most races raise the entry fee in tiers and can sell out without warning — sign up early if you're committed.
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