Boulderthon powered by lululemon: The Boulder Marathon
About the Event
Boulderthon returns on September 26, 2027, presented this year by lululemon. This renowned marathon is one of the fastest-growing races in the United States and has been recognized as one of America's top ten marathons for three consecutive years by USA Today. Runners World also ranks it among the best fall marathons across the country. The event offers a variety of distances to cater to all levels, including a 5K, 10K, half marathon, full marathon, and even a fun run for kids. Participants can look forward to receiving a choice between two lululemon long sleeve tops — either the Metal Vent Tech or Swiftly Tech styles, both valued at $88. Race day promises stunning fall scenery as runners navigate through Boulder's picturesque landscapes and challenging terrain. The event is known for its vibrant atmosphere and enthusiastic community support, making it an unforgettable experience for all participants. Don't miss your chance to join thousands of runners in this annual sell-out race that celebrates the beauty of Colorado during one of the most spectacular times of year. Register now to secure your spot at Boulderthon and be part of a truly memorable running event.
Races Offered
Half Marathon
Sep 26, 2027
straighten
Distance —
21.1K
terrain
Type —
Running
timer
12:30
sell
$155.00
Heart to Heart 5K Presented by BCH
Sep 26, 2027
straighten
Distance —
5K
terrain
Type —
Running
timer
13:00
sell
$45.00
10K Presented by Cheribundi
Sep 26, 2027
straighten
Distance —
10K
terrain
Type —
Running
timer
13:30
sell
$64.00
Kids Run
Sep 26, 2027
straighten
Distance —
0.6K
terrain
Type —
Running
timer
14:30
sell
$29.00
Marathon
Sep 26, 2027
straighten
Distance —
42.2K
terrain
Type —
Running
timer
15:00
sell
$165.00
Weather History
These values represent the 3-year monthly averages for September in Boulder.
thermostatTemperature
10.0° / 25.8°
wb_sunnyFeels 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.
