Saint-Pierre, RE · October 2026
Diagonale des Fous
Diagonale des Fous pacing strategy with effort-based splits, nutrition timing, and course-specific risk notes for the 180 km ultra.
- Distance
- 180.00 km
- Elevation gain
- 7822 m
- Typical temp
- 12–28 °C
- Cutoff
- 66:00:00
The short version
A brutal course
- ▸Big climbing day — 7822 m up. Pace the ascents on effort, not the clock.
- ▸Low sun in your eyes around km 75 — bring a cap or shades.
- ▸Full overhead sun from km 91 — sunscreen and run the shaded side.
Next edition
15 October 2026
Typical race-day conditions
12–28 °C
We lock the real forecast into your plan in race week.
Course difficulty
BrutalDriven by 7822 m of climbing, altitude up to 2488 m, 7774 m of quad-pounding descent. Harder than CCC by UTMB (10.0), easier than Eiger Ultra Trail E101 (10.0) — tougher than 78% of the races we cover.
Race data quality
Medium confidence
Last verified: 24/05/2026
Seeded from public headline race data. Detailed climb/aid/cutoff modeling must be imported before high-confidence paid positioning.
Elevation profile
Verified profile
Paid strategy guardrail
Official race packet remains source of truth
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
20:18:27
Course cost
+378:49
Fuel target
90 g/h
First 5 km preview
full race locked
- km 14:59
- km 25:08
- km 34:57
- km 46:15
- km 56:15
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 Diagonale des Fous 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
Annual
€19
per year, every race
- ✓Everything in Race Pass
- ✓Unlimited races, all year
- ✓Re-plan as your fitness changes
No subscription required — one race is a one-off €7. Cancel anytime on Annual.
Continue with approximate course data →Course elevation
7822 m total gain · 7774 m loss · max 2488 m, min 5 m.
Fly the course
Sun & shade
Sun in your eyes
21 km
Sun on your back
19 km
Side / overhead
53 km
Expect low sun roughly in your eyes around km 75 — pack a peaked cap or shades; low glare hides kerbs and potholes. From km 91 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 22:00:00 start (timezone estimated from longitude), for a mid-pack finishing time.
Aid stations
12 stations on course — plan your fueling around them.
Race overview
Diagonale des Fous is one of the hardest and most culturally important ultras in the world: Reunion island, huge vertical, humidity, technical trails, and very long time-on-feet.
How hard is this course?
Reference table — how the Diagonale des Fous 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 (20 °C / 75 % 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 | Diagonale des Fous finish | Course cost | Adjusted pace |
|---|---|---|---|---|
| Beginner (VDOT 35) | 18:20:16 | 26:36:41 | +45.1% | 6:25/km |
| Intermediate (VDOT 45) | 15:00:14 | 21:46:23 | +45.1% | 5:15/km |
| Trained (VDOT 50) | 13:46:56 | 20:00:01 | +45.1% | 4:49/km |
| Competitive (VDOT 60) | 11:53:28 | 17:15:22 | +45.1% | 4:10/km |
Reference nutrition
For a 70 kg runner finishing in 20:00:01 at 20 °C. Adjust to your weight and tolerance — these are ISSN-window targets, not prescriptions.
- Carbs / hour
- 90 g
- Total carbs
- 1800 g
- Fluid / hour
- 690 ml
- Sodium / hour
- 500 mg
FAQ
How should I pace Diagonale des Fous?
Treat the preview as an effort plan, not a fixed road-marathon pace table. The course model includes 10200 m of climbing, so climbs, descents, heat, and aid-station timing matter more than average pace.
How reliable is the current course data?
Seeded from public headline race data. Detailed climb/aid/cutoff modeling must be imported before high-confidence paid positioning.
Get your personalized strategy
The numbers above are samples. Sign up free and get the full Diagonale des Fous strategy from your VDOT, the current course model, Open-Meteo race-week forecast when available, and your nutrition preferences.
First race free · €7 per additional race · €19/yr for unlimited
Get my Diagonale des Fous strategyRelated races
- Comrades Marathon· Pietermaritzburg887 m gain · typical 7–21 °CDiagonale des Fous vs Comrades Marathon — which is harder? →
- Marathon des Sables Legendary· Merzouga2000 m gain · typical 18–38 °CDiagonale des Fous vs Marathon des Sables Legendary — which is harder? →
- Two Oceans Marathon· Cape Town699 m gain · typical 14–21 °CDiagonale des Fous vs Two Oceans Marathon — which is harder? →
- Ultra-trail Cape Town 100 Miler· Cape Town4213 m gain · typical 12–25 °CDiagonale des Fous vs Ultra-trail Cape Town 100 Miler — which is harder? →
New to trail and ultra pacing? Start with our trail and ultra pacing guide or run the VDOT calculator.