The 2026 Boulder Rez Marathon has concluded.

Boulder Rez Marathon

Race complete

Boulder, CO, USA · August 15, 2026

60°·79° high·Light·Dry

Race Day Weather

60°at start

79° high

Light

Dry

Warm afternoon, steady breeze

Runners will face a temperature rise from 59°F at the start to a warm 79°F by the finish. Winds will be light at 7 mph from the SSW, with gusts up to 21 mph. With humidity at 62%, pacing adjustments are advised as the race progresses, particularly in the warmer afternoon.

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Pace Calculator

Distance: 26.2mi

Target Finish Time

0:00:00

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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 79°F and a low of 59°F with a 100% 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:57° 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	61°/90°	-	44°
2024 Boulder Rez Marathon Clear conditions throughout the day. 2024	70°/95°	-	42°
2023 Boulder Rez Marathon Partly cloudy throughout the day. 2023	65°/82°	-	50°
2022 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2022	72°/86°	-	53°
2021 Boulder Rez Marathon Clear conditions throughout the day. 2021	66°/88°	-	54°
2019 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2019	59°/74°	-	45°
2018 Boulder Rez Marathon Partly cloudy throughout the day with late afternoon rain. 2018	40°/45°	-	38°
2017 Boulder Rez Marathon Clear conditions throughout the day. 2017	30°/55°	-	29°
2015 Boulder Rez Marathon Cloudy skies throughout the day. 2015	49°/54°	-	49°

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