Chamonix, FR · August 2027
UTMB Mont-Blanc
UTMB Mont-Blanc: 174 km race guide, estimated elevation, typical conditions and a personal pacing and nutrition preview.
- Distance
- 174.00 km
- Elevation gain
- 8381 m
- Typical temp
- 13–24 °C
- Cutoff
- 46:30:00
The short version
A brutal course
- Big climbing day — 8381 m up. Pace the ascents on effort, not the clock.
- Low sun in your eyes around km 4–92 — bring a cap or shades.
- Full overhead sun from km 118 — sunscreen and run the shaded side.
Next edition
August 2027
Typical race-day conditions
13–24 °C
We lock the real forecast into your plan in race week.
Course difficulty
BrutalDriven by 8381 m of climbing, altitude up to 2515 m, 8381 m of quad-pounding descent. Harder than Ultra-trail Cape Town 100 Miler (10.0), easier than Western States 100 (10.0) — tougher than 98% of the races we cover.
Race data quality
Medium confidence
Edition-specific course details have not been human-verified
Elevation values are estimates derived from the stored route profile, not official surveyed measurements. Confirm the final route, aid-station positions and supplies with the organizer for your edition.
Elevation profile
Approximate course model
Paid strategy guardrail
Official race packet remains source of truth
- Open-Meteo historical climate archive (2022–2024)
Step 1 · Free preview
See the course-adjusted plan first
Enter one recent result. The preview returns course cost, first splits, and fuel target from the deterministic engine and the current course data model.
VDOT
49.1
Estimate
21:16:26
Course cost
+464:47
Fuel target
60 g/h
60 g/h needs a trained gut — practise it in training, never try new fuelling on race day. Your full plan tunes this to your experience.
First 5 km preview
full race locked
- km 15:00
- km 25:02
- km 35:10
- km 44:56
- km 55:00
First race free · then €7 Race Pass · no monthly subscription
Uses an approximate course model; verify final logistics against the official race packet.
Step 2 · Your full UTMB Mont-Blanc plan
The preview shows the shape. The plan races it for you.
Course preview
Free
what you see now
- Difficulty score & course data
- Course-cost & toughest km
- Your first full plan free, ever
Race Pass
€7
one-time, this race
- Every km split, weather-adjusted
- Nutrition & fluid timeline
- Heat, wind & sun race tactics
- Danger zones + watch file (GPX)
- Race-week forecast & reminders
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per year, every race
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Continue with approximate course data →Course elevation
8381 m total gain · 8381 m loss · max 2515 m, min 814 m.
Fly the course
At Tour du Mont-Blanc loopSun & shade
Sun in your eyes
28 km
Sun on your back
16 km
Side / overhead
54 km
Expect low sun roughly in your eyes around km 4–92 — pack a peaked cap or shades; low glare hides kerbs and potholes. From km 118 the sun sits high overhead — peak UV and radiant heat, so keep sunscreen on and run the shaded side of the road where you can.
Approximate — solar position from the route geometry and a 17:45:00 start (timezone estimated from longitude), for a mid-pack finishing time.
Signature sections
Tour du Mont-Blanc loop · km 0–174
Long alpine climbs, technical descents, night running, and altitude exposure around the Mont-Blanc massif.
Aid stations
11 listed aid-station references. Confirm positions and available supplies with the organizer for your edition.
Race overview
UTMB Mont-Blanc is a 174 km event in Chamonix. The stored course model estimates 8381 m of ascent and 8381 m of descent. Elevation is an estimate, not an official surveyed measurement. The historical climate baseline is 13–24 °C with 65% relative humidity. This is not the race-day forecast. Use a recent result to build a personal pacing and fuel plan. Check the final route and aid-station services against the organizer's instructions for your edition.
How hard is this course?
Reference table — how the UTMB Mont-Blanc compares to a flat sea-level course for four typical fitness levels. Computed from the route profile, mean course altitude, and typical race-week climate (19 °C / 65 % humidity). Your personal strategy uses your VDOT, per-km splits, nutrition timing, and the typical climate baseline for this static sample; paid strategies use Open-Meteo when a verified race date is inside the forecast window.
| Runner | Flat-course finish | UTMB Mont-Blanc finish | Course cost | Adjusted pace |
|---|---|---|---|---|
| Beginner (VDOT 35) | 17:43:36 | 27:52:40 | +57.3% | 6:30/km |
| Intermediate (VDOT 45) | 14:30:13 | 22:48:33 | +57.3% | 5:19/km |
| Trained (VDOT 50) | 13:19:22 | 20:57:07 | +57.3% | 4:53/km |
| Competitive (VDOT 60) | 11:29:41 | 18:04:38 | +57.3% | 4:13/km |
Reference nutrition
For a 70 kg runner finishing in 20:57:07 at 19 °C. Adjust to your weight and tolerance — these are ISSN-window targets, not prescriptions.
- Carbs / hour
- 60 g
- Total carbs
- 1257 g
- Fluid / hour
- 665 ml
- Sodium / hour
- 500 mg
FAQ
How far is UTMB Mont-Blanc?
The distance in this course model is 174 km. Check the organizer's final course information for your edition.
How much climbing is in UTMB Mont-Blanc?
The stored course model estimates 8381 m of ascent and 8381 m of descent. Elevation is an estimate, not an official surveyed measurement.
What weather can I expect at UTMB Mont-Blanc?
The historical climate baseline is 13–24 °C with 65% relative humidity. This is not the race-day forecast.
When does UTMB Mont-Blanc start and what is the cutoff?
The typical start is 17:45 local time and the stored cutoff is 46:30:00. Confirm your edition, wave and cutoff rules with the organizer.
Can I rely on the listed aid stations?
Aid-station positions and services are planning references until confirmed against your edition’s official race packet. Carry your practiced fuel unless the organizer confirms it is provided.
Get your personalized strategy
The numbers above are samples. Sign up free and get the full UTMB Mont-Blanc strategy from your VDOT, the current course model, Open-Meteo race-week forecast when available, and your nutrition preferences.
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New to trail and ultra pacing? Start with our trail and ultra pacing guide or run the VDOT calculator.