Boulder Rez Marathon

Boulder, CO, USA • August 15, 2026

Race Day Weather

clear-day
61°
86° high
Light
Dry

Warm day, adjust pace early

Runners will face a rising temperature trend from 62°F at the start to a peak of 86°F. With a gentle headwind of 6 mph and low humidity at 40%, hydration will be crucial. Runners should consider starting conservatively to manage the heat as the race progresses.

Race day forecast available in 141 days
clear-night8
clear-night8
clear-day8
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clear-day8
clear-day8
clear-day8
clear-day7
clear-day7
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partly-cloudy-day7

Pace Calculator

Distance: 26.2mi
0:00:00
HH:MM:SS
Pace
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Weather Adj.
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Common Goals:

This amazing run course will take you alongside the Boulder Reservoir, remaining mostly on dirt roads and trails. The course is flat with only 200 feet of gain, and will provide views of the Boulder Reservoir and Rocky Mountains. Source

Area Map

Course Map

Course Map Unavailable

We don't have course map data for Boulder Rez Marathon yet. If you have a GPX file (or other format) for this race, we'd love to add it!

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FAQ

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When is the 2026 Boulder Rez Marathon?

The 2026 Boulder Rez Marathon will be held on Saturday August 15, 2026.

Is the Boulder Rez Marathon a Boston Marathon Qualifier?

Yes, the Boulder Rez Marathon is an official Boston Marathon qualifier.

Historical Weather

Based on 9 years of data
Avg Temp
74°F
L:53° H:74°
RunScore
7
Conditions
Rain Freq
0%
0 of 9 yrs
Wind5mph
Dew43°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScoreResults

2025 Boulder Rez Marathon

Clear conditions throughout the day with late afternoon rain.

2025
clear-day
54°/90°-
8

2024 Boulder Rez Marathon

Clear conditions throughout the day.

2024
clear-day
63°/95°-
7

2023 Boulder Rez Marathon

Partly cloudy throughout the day.

2023
clear-day
64°/82°-
7

2022 Boulder Rez Marathon

Partly cloudy throughout the day with late afternoon rain.

2022
clear-day
67°/86°-
8

2021 Boulder Rez Marathon

Clear conditions throughout the day.

2021
clear-day
61°/88°-
7

2019 Boulder Rez Marathon

Partly cloudy throughout the day with late afternoon rain.

2019
clear-day
54°/74°-
8

2018 Boulder Rez Marathon

Partly cloudy throughout the day with late afternoon rain.

2018
partly-cloudy-night
38°/45°-
8

2017 Boulder Rez Marathon

Clear conditions throughout the day.

2017
clear-night
29°/55°-
7

2015 Boulder Rez Marathon

Cloudy skies throughout the day.

2015
cloudy
47°/54°-
8
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