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Boulderthon powered by lululemon: The Boulder Marathon

Boulder, Colorado, United States

calendar_today 27 Sep, 2026

directions_run Running

sell $29.00 – $169.00

About the Event

Boulderthon, presented this year by lululemon, invites runners to join one of America's fastest-growing marathons. Recognized as part of USA Today's top 10 US races for three consecutive years and named among the Best Fall Marathons by Runners World, Boulderthon offers a diverse lineup that caters to all levels of experience—options range from a challenging marathon distance through scenic Colorado routes down to kid-friendly runs.
This year’s event promises an exclusive merchandise shop featuring limited-edition lululemon x Boulderthon gear. Race participants will receive their choice of either the Metal Vent Tech or Swiftly Tech long sleeve shirts, both valued at $88—a perk for all entrants looking to add a premium piece to their running collection.
Experience firsthand why runners across the country have flocked to Colorado’s premier autumn event and savor the stunning fall foliage while traversing varied terrain. Don’t miss out on securing your spot in this must-participate race known for its breathtaking setting, enthusiastic crowd support, and high-energy atmosphere that celebrates every runner's achievement.
Join Boulderthon today before spaces fill up—embrace a truly memorable racing experience amidst the vibrant backdrop of Colorado’s fall season.

Races Offered

Half Marathon

Sep 27, 2026

straighten

Distance — 21.1K

terrain

Type — Running

timer

12:30

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US$159.00

Marathon

Sep 27, 2026

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Distance — 42.2K

terrain

Type — Running

timer

12:30

sell

US$169.00

Heart to Heart 5K Presented by BCH

Sep 27, 2026

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Distance — 5K

terrain

Type — Running

timer

13:00

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US$54.00

10K Presented by Cheribundi

Sep 27, 2026

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Distance — 10K

terrain

Type — Running

timer

13:30

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US$69.00

Kids Run

Sep 27, 2026

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Distance — 0.6K

terrain

Type — Running

timer

14:30

sell

US$29.00

Weather History

These values represent the 3-year monthly averages for September in Boulder.

thermostat Temperature

10.0° / 25.8°

wb_sunny Feels like

7.7° / 23.0°

light_mode Avg sunshine hours

11h 18m

water_drop Avg rainfall

1.1 mm

ac_unit Avg snowfall

—

air Avg wind speed

7.0 km/h (Light breeze)

opacity Sweat loss rate

Moderate

terrain Course conditions

Firm and slightly soft

sunny Max UV Index

Moderate (5.0)

humidity_mid Humidity

48.5%

wb_twilight Sunrise

06:42

nightlight Sunset

19:08

About Boulder

Learn more about the host city, Boulder.

Boulder is a college town of about 106,000 in the Front Range region of Colorado. The home of the University of Colorado, the city has a reputation for progressive values and outdoor recreation. It is a very pleasant place to live and visit.