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17th Annual F^3 Lake Half Marathon & 5k

Name: 17th Annual F^3 Lake Half Marathon & 5k
Start: 2026-01-31
End: 2026-01-31
Location: Chicago, Illinois

location_city Chicago

location_on Illinois

flag United States

calendar_today 31 Jan, 2026

directions_run Running

language Official Website

About the Event

The 17th 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 our great hoodies and a medal! We will return to the warm confines of Soldier Field's United Club! The UC opens at 8 a.m. Gear check is available. The half marathon starts at 10 a.m. and consists of self-seeded waves in quick succession. The 5k is scheduled for 10:30 a.m. Courses close at 1:30 p.m.

After the race, head to Weathermark Tavern for the afterparty! 1503 S. Michigan Ave. Free participant photos are always uploaded to flashframe.io

Races Offered

Half Marathon

Jan 31, 2026

straighten

Distance — 13.1 Miles

terrain

Type — Road running

timer

10:00

5k

Jan 31, 2026

straighten

Distance — 5K

terrain

Type — Road running

timer

10:30

Weather Overview

These values represent the 3-year monthly averages for January in Chicago.

Temp (°C)

Feels Like (°C)

thermostat -6.8° / 0.1°

wb_sunny -13.3° / -5.6°

Wind (km/h)

Humidity (%)

air 18.5 /

water_drop 77.8%

Temp (°C)

Feels Like (°C)

Wind (km/h)

Humidity (%)

thermostat -6.8° / 0.1°

wb_sunny -13.3° / -5.6°

air 18.5 km/h

water_drop 77.8%

About Chicago

Chicago is the home of the blues and the truth of jazz, the heart of comedy and the idea of the skyscraper. Here, the age of railroads found its center, and airplanes followed suit. "Stormy, Husky, Brawling / City of Big Shoulders," Chicago is a Heartland boomtown, its ethos defined by urban planner Daniel Burnham's immortal vision: "Make no little plans; they have no magic to stir men's blood." It is one of the world's great cities and the third largest city in the United States, behind only New York City and Los Angeles.