Endurance Grid lists 8 races in Thornton, Colorado, from August 2026 to June 2027.
The race calendar
The Thornton race calendar is busiest in September, October, and June. Every race here is a running event, so there's usually one near you. You'll see distances like 5K, 10 Mile, 10K, and 1K.
Weather on race day varies by time of year, so it lives where it’s accurate — each race page shows that race’s typical high, low, and rain chance from NOAA climate normals for its venue and date.
Population
142,878
as of 2023
City Elevation
5,347 ft
Nearest Airport
DEN
Denver International Airport
Time Zone
Mountain Time
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Just Outside Thornton