Boulderthon Marathon
Boulder, CO, USA • September 27, 2026
Race Day Weather
51°
75° high
Light
Dry
Warming day, light winds
Runners will face a temperature rise from 52°F at the start to a warm 75°F by the finish. Wind will be light at 5 mph from the ESE, creating minimal resistance. With humidity at 40% and a dew point of 37°F, conditions remain comfortable, but runners should consider adjusting their pace as temperatures climb.
Race day forecast available in 184 days
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Distance: 26.2mi
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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.