Boulderthon Half Marathon

Boulder, CO, USA · September 26, 2027·
partly-cloudy-night64°·84° high·Windy·Dry
6
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Race day weather currently unavailable.

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Race Plan

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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 Boulderthon Half Marathon runs 13.1 miles through Boulder, Colorado, starting at 19th and Pearl Street. The route heads east along Pearl Parkway to Valmont Road, turns north on 61st and 63rd Streets to Jay Road, then comes back south and west on 57th Street and Independence Road. It returns to downtown by the 4 Mile Creek Trail and Folsom Street and finishes at 16th and Spruce Streets. The course is on paved roads and paved paths at about 5,300 feet of elevation, with roughly 385 feet of total climbing.

Race weekend

Sunday, September 26
7:00 AMMarathon (26.2 mi)
7:00 AMHalf Marathon (13.1 mi)
7:45 AM5K (3.1 mi)8:10 AM10K (6.2 mi)

FAQ

When is the 2027 Boulderthon Half Marathon?

The 2027 Boulderthon Half Marathon will be held on Sunday September 26, 2027.

What will the weather be like for the 2027 Boulderthon Half Marathon?

The forecast calls for a high of 84°F and a low of 59°F with a 0% chance of rain. Check our detailed hourly forecast above for the best half marathon race plan.

Historical Weather

Based on 6 years of data
Avg Temp
54°F
L:50° H:59°
RunScore
9
Conditions
Rain Freq
0%
0 of 6 yrs
Wind1mph
Dew36°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScoreResults
2026
partly-cloudy-day
64°/73°-
7
2025
clear-day
52°/59°-
9
2024
clear-day
57°/66°-
8
2023
clear-night
44°/55°-
10
2022
clear-night
41°/52°-
10
2021
clear-night
42°/46°-
10