Arc 100M is the 173km ultra trail at Arc of Attrition by UTMB 2027 (Perranporth, United Kingdom). The race starts on January 22, 2027 at 01:00 PM. The time limit is 37 h.
The course climbs 5507m+. With 32m/km of climbing, this is a rolling, mostly runnable course. By gradient, 27% of the distance is uphill, 27% downhill and 47% flat. Surface: 54% trail, 21% smooth, 18% road, and 6% technical. Flat-equivalent effort: 240.9 FlatKM.
Poles bring little benefit here: only about 1.1km of pole-friendly terrain.
Quad damage risk is moderate (index 39 of 100), with 53% of the load in the first half: 0 descents deserve a plan and a couple of downhill sessions before race day.
On race day, start temperatures have historically ranged from 7°C to 11°C, with around 9°C at the highest point; the chance of precipitation is about 55%. Heavy rain of 10.0mm or more falls on about 11% of days around this date.
This page has a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Arc 100M.
Other distances of Arc of Attrition by UTMB 2027Arc 100K (82.7km)·Arc 50K (49.4km)·Arc 20K (22.1km)
Other editions of Arc 100M2026·2025
Official websitearcofattrition.utmb.world
