Boulder Rez Marathon

Boulder, CO, USA · August 15, 2026

62°·85° high·Light·Dry

Weather

Race Day Weather

62°at start

88° high

Light

Dry

Warm afternoon, adjust pace wisely

Runners will face temperatures rising from 62°F at the start to 87°F by the finish, with average humidity at 41%. A light headwind at 7 mph may provide some relief, but the heat will necessitate pacing adjustments. It's advisable to hydrate frequently and consider a conservative start to manage the warming conditions.

Race day forecast available in 69 days

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Distance: 26.2mi

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Race Info

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

Website

Course Map

FAQ

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.

What will the weather be like for the 2026 Boulder Rez Marathon?

The forecast calls for a high of 89°F and a low of 61°F with a 5% chance of rain. Check our detailed hourly forecast above for the best marathon race plan.

Historical Weather

Based on 9 years of data

Avg Temp

74°F

L:53° H:74°

RunScore

Conditions

Rain Freq

0 of 9 yrs

Wind5mph

Dew43°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

Year	Low / High	Rain	Dew Point
2025 Boulder Rez Marathon Clear conditions throughout the day with late afternoon rain. 2025	54°/90°	-	45°
2024 Boulder Rez Marathon Clear conditions throughout the day. 2024	63°/95°	-	43°
2023 Boulder Rez Marathon Partly cloudy throughout the day. 2023	64°/82°	-	50°
2022 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2022	67°/86°	-	53°
2021 Boulder Rez Marathon Clear conditions throughout the day. 2021	61°/88°	-	54°
2019 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2019	54°/74°	-	46°
2018 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2018	38°/45°	-	38°
2017 Boulder Rez Marathon Clear conditions throughout the day. 2017	29°/55°	-	29°
2015 Boulder Rez Marathon Cloudy skies throughout the day. 2015	47°/54°	-	48°

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