Kasterlee - Natuurmarathon 2026
The forecast arrives five days before the start.
Here you'll find the elevation profile, an estimated finish time based on your UTMB Index and details of the 8 aid stations to plan your nutrition and hydration segment by segment.
What's your time based on your UTMB?
Times estimated by the RAVIT model, learned from real ultra-trail finish times. Enter your UTMB Index (utmb.world) to get a personalized estimate.
Cut-off times and crew - Kasterlee - Natuurmarathon · 2026
Data from the official race rules, checked for every edition. The race rules prevail. Positions are interpolated along the GPX track and are a guide, not official course marking.
What you'll find at each aid station
| Product | 1km 5.0 | 2km 10.0 | 3km 15.0 | 4km 20.0 | 5km 25.0 | 6km 30.0 | 7km 35.0 | 8km 40.0 |
|---|---|---|---|---|---|---|---|---|
| Water | available | available | available | available | available | available | available | available |
| Brand products · NamedSport | available | available | available | available | available | available | available | available |
La feuille de ton assistance pour Kasterlee - Natuurmarathon · 2026
Les règles d'assistance de cette course ne sont pas encore connues : tu marqueras tes rendez-vous toi-même.
Recto, verso et planche d'étiquettes, en PDF : l'exemple d'une coureuse de l'UTMB.
Elevation profile
The course and its aid stations
Kasterlee - Natuurmarathon: times, aid-station stops and fuelling needs by UTMB® Index
Between a UTMB® Index of 500 and 800, the estimated finish time on this race runs from 4h24 to 2h51, and the aid-station stop budget from 0h05 to 0h02. The longer the race, the more stops weigh: this is time you should plan to spend standing still, not only running.
Source
Below a UTMB® Index of roughly 390, the overall cut-off of 5h30 is no longer reachable at the estimated pace.
| UTMB® Index | Estimated time | Of which stops | Night hours | Carbs | Fluid | Sodium | Cut-off margin |
|---|---|---|---|---|---|---|---|
| 500 | 4h24 | 0h05 | — | 264 g | 3.1 L | 2,202 mg | +1h06 |
| 550 | 4h03 | 0h04 | — | 243 g | 2.8 L | 2,024 mg | +1h27 |
| 600 | 3h44 | 0h04 | — | 224 g | 2.6 L | 1,866 mg | +1h46 |
| 650 | 3h29 | 0h03 | — | 209 g | 2.4 L | 1,738 mg | +2h01 |
| 700 | 3h15 | 0h03 | — | 195 g | 2.3 L | 1,627 mg | +2h15 |
| 750 | 3h03 | 0h03 | — | 183 g | 2.1 L | 1,525 mg | +2h27 |
| 800 | 2h51 | 0h02 | — | 171 g | 2 L | 1,421 mg | +2h39 |
Figures based on 60 g of carbohydrate, 700 mL of fluid and 500 mg of sodium per hour, "average" preparation and mild conditions (15–25 °C). Above 25 °C, count on roughly 900 mL/h and 700 mg/h. Carbohydrate intake is trained: 60 g/h is a floor, 90 g/h assumes a glucose-fructose blend and a gut used to it.
Other trails worth preparing for
- Vissenaken - 29km29 km · 229 m D+ · November 22, 2026
- Trail du BW - 42km41 km · 878 m D+ · December 5, 2026
- Trail du BW - 62 km62 km · 1,207 m D+ · December 5, 2026
- Maredsous - 30km-night30 km · 682 m D+ · December 18, 2026
- Hombourg - 29km29 km · 712 m D+ · December 19, 2026
- TDLS - Ultra Trail de la Sibérie - BE - 35K35 km · 1,383 m D+ · February 20, 2027
- TDLS - Ultra Trail de la Sibérie - BE - 57K52 km · 1,646 m D+ · February 20, 2027
- TDLS - Ultra Trail de la Sibérie - BE - 42km43 km · 1,525 m D+ · February 20, 2027
- Bossière - 33km33 km · 481 m D+ · October 18, 2026
Sources and method
- Time projection — times by UTMB Index are taken from the actual splits of runners in each level band on previous editions of this race, aid station stops included. No formula is used as long as these results exist.
- Trail nutrition — hourly targets for carbohydrate, fluid and sodium follow the commonly accepted ultra-endurance guidance. La Clinique du Coureur — Fuelling in trail running
- Course, aid stations and cut-offs — taken from the event's official rules, which prevail in case of any discrepancy. Official site — Kasterlee - Natuurmarathon
Weather for Kasterlee - Natuurmarathon
The weather for Kasterlee - Natuurmarathon will appear here as soon as the forecast models reach that date, around five days before the start: feels-like temperature, rain, snow, wind and storms, section by section and at your passage time.
Detailed weather for Kasterlee - Natuurmarathon, hour by hour on the courseFrequently asked questions
How many checkpoints?
Kasterlee - Natuurmarathon has 9 checkpoints: 8 aid stations and 1 checkpoint with undocumented contents. Details are in the two tables above.
What's the longest segment without aid?
The one leading to Ravitaillement 1: 5.0 km and 13 m elevation gain. That's the one to load up for first.
How do I find the exact location of an aid station?
The Google Maps icon in the “Access” column opens the aid station's location: handy for planning your crew's routes.
What distance and elevation gain?
Kasterlee - Natuurmarathon is 43 km long with 200 m of elevation gain.
How long to finish?
With a UTMB Index of 600 (average runner), the estimated time is around 3h44 for Kasterlee - Natuurmarathon.
What's the weather forecast?
The weather for Kasterlee - Natuurmarathon will be published on this page around five days before the start, once the forecast models reach the race date. It will be detailed section by section: feels-like temperature, rain, snow, wind and storms.
Want to stack the odds in your favor for Kasterlee - Natuurmarathon?
In 2 minutes, RAVIT generates your complete plan: segment-by-segment time, carbs, water and sodium at every aid station, printable roadbook.
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