Chamonix, Chamonix, France · Friday, June 25, 2027

50 mi

Mont-Blanc 90K

230 days away
90 km Distance
6,140 m Climbing
10.0 Grit · Elite / extreme
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45.9237° N, 6.8694° E© OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Climbing rate 68 m / km Mountain. Significant climbing. Steep sections will require power hiking.
Time limit 24 hours 16:00 min/km average. Generous. Walkable throughout for most of the field. More forgiving than 90% of 50 mi races. Measured against 486 races of the same distance. Cut-off calculator →
Field size ~689 Very large. Congested start, busy aid stations.

DUV results for the 2025 edition (92km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, June

Daytime high 16°C
Night low 7°C
Rainfall Showers likely
Daylight 15 h 44 m of light

Regional 2001-2020 average for June — 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

Gear for this race

Chosen for 90 km of mountain with 6,140 m of ascent.

HOKA

Speedgoat 6

Max-cushion trail shoe with Vibram Megagrip outsole, ideal for rocky mountain terrain.

$155 ★★★★★ 4.7

Salomon

S/Lab Ultra 3

Premium ultra trail shoe with Advanced Chassis for stability on technical terrain.

$200 ★★★★★ 4.8

Maurten

Gel 100

Hydrogel technology for 25g carbs per gel with minimal GI distress.

$3.5 ★★★★★ 4.7

Salomon

ADV Skin 12

Industry-standard 12L race vest with front flask pockets and minimal bounce.

$180 ★★★★★ 4.8

LEKI

Ultratrail FX.One

Ultra-light carbon folding poles (135g each) designed for mountain ultra racing.

$200 ★★★★★ 4.6

Petzl

NAO RL

1500-lumen reactive lighting headlamp with 15-hour runtime. Automatic brightness adjustment.

$150 ★★★★★ 4.7
All gear guides →

About

It runs during the Marathon du Mont-Blanc weekend.

Highlights

  • Mont Blanc views
  • Chamonix atmosphere
  • Gateway to UTMB

Course Notes

Trail en semi-autonomie, comprenant 5 ravitaillements complets et 3 ravitaillements légers. Un parcours de 92km et 6330m de dénivelé positif et négatif (référence ITRA), sur des sentiers de montagne techniques situés entre 1500m et 2650m d'altitude.

Similar races

Other 50 mi mountain ultras, closest in distance first.