Blue Sky Trail Marathon & Half Marathon is the 42.0km ultra trail at Blue Sky Trail Marathon & Half 2025 (Fort Collins, United States). The race starts on October 19, 2025.
Run the climb at race pace, build your speed on the downhill, and go all out at the finish.
The course climbs 1100m+. With 26m/km of climbing, this is a rolling, mostly runnable course. By gradient, 31% of the distance is uphill, 29% downhill and 40% flat. The longest climb runs 4.9km at an average 5.8% grade (280m of vertical). The longest descent runs 7.4km at an average 5.6% grade (415m of vertical). The steepest climb averages 14.0% over 1.6km. The steepest descent drops at 15.5% over 0.3km. Surface: 67% trail, 9% road, and 6% extreme. Flat-equivalent effort: 49.7 FlatKM.
The course is runnable enough that trekking poles are not needed.
Quad damage risk is low (index 12 of 100): a few descents worth noting, none of them decisive.
On race day, start temperatures have historically ranged from 6°C to 16°C, with around 12°C at the highest point; the chance of precipitation is about 18%.
This page has a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Blue Sky Trail Marathon & Half Marathon.
Other distances of Blue Sky Trail Marathon & Half 2025Blue Sky Trail Marathon & Half Half Marathon (22.0km)
