Boulderthon Marathon
Boulder, CO, USA • September 27, 2026
Race Day Weather
51°
75° high
Light
Dry
Comfortable temps, big temp swing
Mild 51°F temps at gun time mean comfortable early miles without overheating risk. Temps will climb significantly to 75°F by later miles, so expect fading conditions as the race progresses. Light winds shouldn't be a major factor for pacing.
Race day forecast available in 164 days
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Distance: 26.2mi
0:00:00
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Named among the Best Fall Marathons by Runner's World, #5 Best Half Marathon in the US by Active, as well as #1 Best in Colorado and one of the "Most Beautiful Marathons in the World" by HalfMarathons.Net, Boulderthon drew over 6,000 runners from all 50 states and 18 countries in 2023, and has doubled in size every year since its inception. Source
FAQ
When is the 2026 Boulderthon Marathon?
The 2026 Boulderthon Marathon will be held on Sunday September 27, 2026.
Is the Boulderthon Marathon a Boston Marathon Qualifier?
Yes, the Boulderthon Marathon is an official Boston Marathon qualifier.
What is the time limit for the Boulderthon Marathon?
The time limit for the Boulderthon Marathon is 6.5 hours.
What will the weather be like for the 2026 Boulderthon Marathon?
The forecast calls for a high of 75°F and a low of 51°F with a 0% chance of rain.