Ultramarathon

UTMB

UTMB is the 174 km Mont-Blanc loop from Chamonix, a 100M final with 9,900 meters of climbing, major crowds, and a full alpine night out for the field.

Next raceFriday, August 28, 2026
Distance categoryUltramarathon
LocationChamonix-Mont-Blanc, France
Get alertsLast checked August 21, 2026

Quick facts

  • Flagship 100M final of the UTMB World Series Finals in Chamonix.
  • 174 km course with about 9,900 meters of climbing.
  • Entry uses Running Stones, a valid UTMB Index, and the Mont-Blanc registration process.
  • Mountain-weather gear and overnight pacing are central to the full-loop experience.
Race-day forecast

UTMB race-day forecast

Thunderstorms on race day · 17-22°C (62-71°F) · 65% rain · 5 mph wind

Race-day forecast for Friday, August 28, 2026 in Chamonix-Mont-Blanc, Auvergne-Rhone-Alpes, FR. Checked 11:01 PM GMT+2 race-local time. Data: Open-Meteo.

About the UTMB

UTMB is the flagship race of the Mont-Blanc week and one of trail running's highest-demand starts. The full loop around Mont Blanc gives runners an elite destination trail event with major crowds, strict entry requirements, and a long alpine night.

Course

The route loops around Mont Blanc from Chamonix, crossing high alpine terrain in France, Italy, and Switzerland before returning to town. The race lists 174 km, 9,900 meters of climbing, and a 46 hour 45 minute cutoff.

Race-day weather

Late August can bring warm valley miles, cold nights, rain, wind, or snow at altitude. Runners need mountain-weather gear and pacing discipline because conditions can change repeatedly across the full loop.

Past UTMB dates and results

YearDateStatusResults
2026Friday, August 28, 2026Upcoming
2025Friday, August 29, 2025CompletedOpen results
2024Friday, August 30, 2024CompletedOpen results

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UTMB FAQ

When is the UTMB?

The 2026 UTMB is on Friday, August 28, 2026.

Does the UTMB have live tracking?

Yes. Live tracking is available at live.utmb.world.

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