INTERSPORT SPEED 15K is the 15.0km trail race at Julian Alps Trail Run by UTMB 2025 (Kranjska Gora, Slovenia). The race starts on September 19, 2025.
Run easy on the first mountain, then go all out on the second.
The course climbs 550m+. With 37m/km of climbing, this is a rolling, mostly runnable course. By gradient, 31% of the distance is uphill, 24% downhill and 46% flat. The longest climb runs 5.0km at an average 4.4% grade (221m of vertical). The longest descent runs 5.4km at an average 3.7% grade (200m of vertical). The steepest climb averages 34.2% over 0.3km. The steepest descent drops at 16.4% over 0.3km. Surface: 59% trail and 39% road. Flat-equivalent effort: 21.1 FlatKM.
The course is runnable enough that trekking poles are not needed.
Quad damage risk is low (index 8 of 100): a few descents worth noting, none of them decisive.
On race day, start temperatures have historically ranged from 9°C to 18°C, with around 13°C at the highest point; the chance of precipitation is about 42%.
627 finishers completed the 2025 edition. Men's winner: Adrian Brănescu (Romania) in 1:14:18. Women's winner: Julia Rath (Germany) in 1:27:29.
This page has the full results and splits, a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for INTERSPORT SPEED 15K.
Other distances of Julian Alps Trail Run by UTMB 2025I Feel Slovenia 120K (124km)·Lake Bled 80K (80.0km)·Sky Trail 50K (50.0km)·Kranjska Gora 25K (25.0km)·FUNNY 10K (10.0km)
Other editions of INTERSPORT SPEED 15K2026
Official websitejulianalps.utmb.world