Chamonix, Chamonix, France · Friday, August 27, 2027

100 mi

Ultra-Trail du Mont-Blanc

293 days away

171 km Distance

10,000 m Climbing

10.0 Grit · Elite / extreme

45.9237° N, 6.8694° E© OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Climbing rate 58 m / km Mountain. Significant climbing. Steep sections will require power hiking.

Time limit 46.5 hours 16:19 min/km average. Generous. Walkable throughout for most of the field. More forgiving than 87% of 100 mi races. Measured against 46 races of the same distance. Cut-off calculator →

Field size ~1,681 Very large. Congested start, busy aid stations.

DUV results for the 2026 edition (174km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, August

Daytime high 18°C

Night low 8°C

Rainfall Showers likely

Daylight 13 h 37 m of light

Regional 2001-2020 average for August — NASA POWER, grid elevation 1714 m. Not a forecast.

The Aid Station

Course-specific beta from the community

⛰️ terrain

This is a mountain course. Poles are highly recommended for the sustained climbs.

By UltraHub Expert

👟 gear

With mountain terrain, choose a shoe with aggressive lugs (5mm+) for optimal performance.

By UltraHub Expert

🥤 nutrition

For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.

By UltraHub Expert

Gear for this race

Chosen for 171 km of mountain with 10,000 m of ascent.

Trail Running Shoes58 m of climb per kilometre — grip and rock protection before cushioning.
Race NutritionPast 171 km the palate quits before the legs do — carry more than one flavour.
Hydration VestsPole attachment and chest-strap stability on steep ground.
Trekking Poles10,000 m of ascent to walk up.
HeadlampsA 46.5 h limit puts you out there after dark.

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