
Fort Collins, United States of America · Saturday 17 October 2026
The event covers a distance of approximately 26.7 miles for the full marathon and 13.4 miles for the half marathon, taking place primarily on dirt singletrack trails with a small portion on rocky paths and dirt roads. The course begins at the Blue Sky Trailhead at Horsetooth Mountain Park, situated west of Fort Collins, Colorado. Runners traverse a north-south route through the easternmost hogbacks of Northern Colorado's Front Range, moving between Horsetooth Mountain Park and Devil's Backbone O
Adjusted Time
4:30:42
Time difference: +30.7 minutes compared to a flat, road, temperate course.
Blue Sky Marathon is a full marathon held in Fort Collins, United States of America, scheduled for Saturday 17 October 2026. The course is run on road surface with 1064m of total elevation gain, reaching a maximum altitude of 1982m above sea level. For registration and full race details, visit the official Blue Sky Marathon website.
This is a very challenging course with 1064m of total elevation gain — significantly more than the average road marathon. The route ranges from 1626m to 1982m above sea level (356m range). Hill training is essential, and runners should expect a significantly slower time compared to a flat course.
Based on historical weather data for October, the expected race day conditions are as follows. Near-ideal running temperatures are expected, ranging from -1°C to 21°C. This temperature range is widely considered optimal for marathon performance, allowing efficient heat dissipation without cold-related issues. There is a low chance of rain (0%), so dry conditions are likely.
Blue Sky Marathon is run on road surfaces, which provide the fastest and most predictable conditions for marathon running. Road courses allow for consistent pacing and are typically the best choice for runners targeting a personal best time.
Our difficulty rating for Blue Sky Marathon is calculated using a model that combines elevation gain, temperature impact, and surface type. Use the difficulty calculator above to enter your target finish time and see exactly how many minutes this course would add or subtract compared to a perfectly flat, cool, road-based marathon. Faster runners and slower runners are affected differently by the same course conditions, so the difficulty is personalised to your pace.
Looking for an easier marathon or a tougher challenge? You can also compare Blue Sky Marathon against other marathons to find the right race for your goals.
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