Race calendar · October 2026 · Colorado
Every Half Marathon in Colorado in October 2026, all 13 of them, sorted by date. Dates, entry fees, finish-time stats from past results, and start-line maps.
13 Half Marathon races in October 2026
What the field actually runs
How we calculate these stats: RunSesh calculates these figures from the most recent published results of past editions, sourced from RunSignup. We show aggregates only: field size, winning and median times, and the cutoff. We never publish individual finisher tables. Last updated Sep 22, 2026.
When in October
Half Marathon races do not spread evenly across October. The busiest weekend is October 10 and October 11, with 6 of them.
By the numbers
The October Half Marathon races that stand out on the numbers: the biggest field, and the longest unbroken run of editions.
The busiest weekend in Colorado is October 10 and October 11, with 6 Half Marathon races on those two days, and the single busiest day is Saturday, October 10 with 4. Every one of them is on a Saturday or a Sunday.
As early as you can. 4 of these October Half Marathon races already have a price increase on the calendar, and 13 are open for entry right now.
The typical entry is $30, with paid entries running from $20 up to $50. Entry fees climb as race day gets closer, so the same race is usually cheapest the week it opens.
Across the 5 of these October Half Marathon races with published results from past editions, the median finisher ran 2:09:24, and the median winning time was 1:19:34. So anything under 2:09:24 puts you in the faster half of a typical field. That is the middle of these RunSignup fields, walkers and charity entrants included, not a national average.
The median one finished 125 runners, across the 5 of these October Half Marathon races with published results from past editions. Most are far smaller than the big-city events people picture, which means less crowding at the start and a friendlier field, with a last recorded finisher at 3:42:41.
Yes, 2 races around Colorado get you off the pavement: 2 mix road and trail. Surfaces are not always published, so it is worth checking a specific race before you register.
September and November sit either side of October, which is where most people look next when a date does not fit.
