Boulderthon – Boulder Marathon

Boulder, United States of America 28 Sep, 2025

The event is a marathon held in Boulder, Colorado, typically scheduled for late September. The course starts by traversing back roads near the foothills of the Flatirons mountain range, then continues into Downtown Boulder, finishing on the pedestrian Pearl Street Mall. The route is described as a loop, run entirely on paved roads.

The course profile is classified as hilly, which indicates that participants can expect notable elevation changes throughout the race, potentially adding to its physical challenge compared to flatter marathons. The exact elevation chart details are not listed, but the hilly terrain and high altitude of Boulder are factors that may influence overall race difficulty, especially for runners not accustomed to these conditions.

The marathon is USATF-sanctioned, implying official course measurement and adherence to competitive standards. Multiple start times are scheduled for various race distances, and the event offers amenities such as reliably measured and clearly marked courses, participant shirts, finisher medals, and awards for overall top finishers and various age groups.

Packet pickup is available on the preceding Friday at a local running store, as well as on race morning at Boulder Reservoir. The course is closed to runners by 2:00pm on race day, indicating a time limit for participants to complete the race.

The event is noted for its scenic setting in Boulder, a city frequently recognized for its outdoor lifestyle and fitness culture. Notable facts include the unique finish location on Pearl Street Mall, the presence of a hilly profile, and the sanctioned status for competitive runners. Volunteer opportunities are extended to all ages, with supervision required for those under 13 years old during their shift.

Generic Marathon Time This represents the time you would expect to run a "generic" marathon in. This is a marathon with around 250 m (800 ft) of elevation gain and a temperature around 10°C (50°F). For best results, use our Race Predictor.

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Boulderthon – Boulder Marathon Time


Statistics

Elevation
Elevation Gain 329 m 1079 ft
Elevation Low 1468 m 4816 ft
Elevation High 1633 m 5358 ft
Weather
Expected Temperature (Low) 12°C 54°F
Expected Temperature (High) 26°C 79°F
Chance of Rain 12%

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The event is a marathon held in Boulder, Colorado, typically scheduled for late September. The course starts by traversing back roads near the foothills of the Flatirons mountain range, then continues into Downtown Boulder, finishing on the pedestrian Pearl Street Mall. The route is described as a loop, run entirely on paved roads.

The course profile is classified as hilly, which indicates that participants can expect notable elevation changes throughout the race, potentially adding to its physical challenge compared to flatter marathons. The exact elevation chart details are not listed, but the hilly terrain and high altitude of Boulder are factors that may influence overall race difficulty, especially for runners not accustomed to these conditions.

The marathon is USATF-sanctioned, implying official course measurement and adherence to competitive standards. Multiple start times are scheduled for various race distances, and the event offers amenities such as reliably measured and clearly marked courses, participant shirts, finisher medals, and awards for overall top finishers and various age groups.

Packet pickup is available on the preceding Friday at a local running store, as well as on race morning at Boulder Reservoir. The course is closed to runners by 2:00pm on race day, indicating a time limit for participants to complete the race.

The event is noted for its scenic setting in Boulder, a city frequently recognized for its outdoor lifestyle and fitness culture. Notable facts include the unique finish location on Pearl Street Mall, the presence of a hilly profile, and the sanctioned status for competitive runners. Volunteer opportunities are extended to all ages, with supervision required for those under 13 years old during their shift.

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