Diagonale du Mont-Joly 2026

La Diagonale du Mont-Joly is a night ski mountaineering race in Saint-Gervais-les-Bains, in the Pays du Mont-Blanc. It starts in the late afternoon, at 5 PM, so racers climb into the evening rather than under full daylight. The event offers two route options, with the Saint-Gervais Vertical Kilometer as one of its main pieces. That Vertical Kilometer is short on paper at 4.7 km, but it climbs all the way to the summit of Mont-Joly. The route gets steep quickly, so a proper warm-up matters, and the upper climb can feel long even for strong racers. The ascent gives wide views over the Mont-Blanc area, and the field can include top ski-mountaineering specialists such as Mathéo Jacquemoud and Pierre Chauvet.