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About RaceIndexOur methodologyData coverageCyclingTriathlon
  • 23K
  • 23 km
  • Chamonix-Mont-Blanc
  • Event dates –
  • Past event

Marathon du Mont-Blanc, Chamonix 23K

This race edition

Race date
Date not confirmed for this distance
Race timezone
Timezone not confirmed
Edition status
Status not confirmed

Entry options

2026 edition

Entry options are not yet confirmed for this edition. Check the organiser before making plans.

Modelled energy-cost change 40.3% versus flat · net elevation 1,007 m

View verified GPS mapOfficial event website ↗
Data current as of Source last verified

Decision summary

Marathon du Mont-Blanc, Chamonix 23K at a glance

Route ascent
1,641 m

Lower than 14% of comparable mapped races

Cut-off average pace
15:39/km

6:00:00 total limit divided by distance. Check gun/chip timing and intermediate limits; allow time for stops.

Typical conditions
67/100

Historical race-date favourability, not a forecast

Evidence depth
15 verified facts

Stored GPS route

Quick answers

What runners ask first

Marathon du Mont-Blanc, Chamonix 23K route map

raceindex.org has a GPS course file for Marathon du Mont-Blanc, Chamonix 23K, so runners can inspect the route line on the map. Elevation charts and ascent figures appear only when that file includes usable elevation data.

How hilly is the Marathon du Mont-Blanc, Chamonix 23K?

The Marathon du Mont-Blanc, Chamonix 23K route has 1,641 m of ascent, 634 m of descent and an estimated 40.3% grade-adjusted pace penalty versus a flat route.

Where does the Marathon du Mont-Blanc, Chamonix 23K route go?

The setting includes waterfront and mountain.

Race character

Scenery

  • Waterfront
  • Mountain
  • Forest
  • Countryside
  • Lakeside

Atmosphere

  • Destination
  • Community
  • Wilderness

Entry, logistics and records

Records and field

Field cap
2,000

Entry requirements

Entry status
Past event: The listed edition date has passed.
Cut-off
6:00:00
Sold out
Yes

Course facts

Notable features
  • A multi-race weekend (90km, 42km, 23km, 10km, KM Vertical, Duo Etoile, Young Race, Mini-Cross) held 25-28 June 2026
  • Eco-conscious entry: 10% of bibs reserved for Chamonix valley residents arriving by public transport/foot/bike, 40% for entrants committing to arrive by train or bus, with mandatory carbon offsets

How hilly is the Marathon du Mont-Blanc, Chamonix 23K?

16%9%15%19%41%
  • Steep descent 16%
  • Descent 9%
  • Flat 15%
  • Climb 19%
  • Steep climb 41%
Total ascent
1,641 m
Net elevation
+1,007 m
GAP factor
40.3%
Longest climb
1,800 m at 17.1%
Gradient mix and ascent are derived from the course geometry under our published normalisation, not taken from organiser marketing.

What are typical race-day conditions?

  • 17°CTypical temperature
  • 7 kphTypical wind
  • 4 mmTypical rainfall
  • 67Favourability /100
Typical conditions for the race date and locality, warmer than the endurance-optimal window. These are climatological norms, not a forecast, and are shared across every distance at this event.

More race details

Is the Marathon du Mont-Blanc, Chamonix 23K flat?

Its normalised GAP factor is 40.3% slower than a flat course, with about 1641 m of total ascent.

How we calculated this

Published facts and derived model outputs on this page are tied to stored sources or a published, version-locked methodology. We show the provenance so runners, coaches and organisers can check it. Data on this page is current as of .

Derived numbers use scoring-methodology-v1.0.

Sources used on this page (3)

Read the full methodology →