Arc of Attrition - Arc 20K 2027
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 2 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 - Arc of Attrition - Arc 20K · 2027
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 | Porthtowankm 9.6 | Finish / Perranporth Airfieldkm 22.1 |
|---|---|---|
| Water | available | available |
La feuille de ton assistance pour Arc of Attrition - Arc 20K · 2027
L'assistance n'est autorisée sur aucun poste de cette course.
Elevation profile
The course and its aid stations
Arc of Attrition - Arc 20K: 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 2h39 to 1h46, and the aid-station stop budget from 0h03 to 0h01. 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 305, the overall cut-off of 4h00 is no longer reachable at the estimated pace.
| UTMB® Index | Estimated time | Of which stops | Night hours | Carbs | Fluid | Sodium | Cut-off margin |
|---|---|---|---|---|---|---|---|
| 500 | 2h39 | 0h03 | — | 159 g | 1.9 L | 1,326 mg | +1h21 |
| 550 | 2h26 | 0h03 | — | 146 g | 1.7 L | 1,220 mg | +1h34 |
| 600 | 2h16 | 0h02 | — | 136 g | 1.6 L | 1,137 mg | +1h44 |
| 650 | 2h08 | 0h02 | — | 128 g | 1.5 L | 1,067 mg | +1h52 |
| 700 | 2h00 | 0h02 | — | 120 g | 1.4 L | 1,002 mg | +2h00 |
| 750 | 1h53 | 0h02 | — | 113 g | 1.3 L | 944 mg | +2h07 |
| 800 | 1h46 | 0h01 | — | 106 g | 1.2 L | 884 mg | +2h14 |
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
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- Eryri by UTMB® - Eryri 25K®25 km · 1,347 m D+ · May 16, 2027
- Skyline Scotland by UTMB® - Aonach Mòr Anarchy®21 km · 938 m D+ · September 19, 2027
- Cartmel - Lakes in a Day Half33 km · 950 m D+ · October 10, 2026
- Kinlochleven - Ben Nevis Skyline28 km · 1,650 m D+ · September 19, 2026
- Kinlochleven - Trail Half Marathon22 km · 386 m D+ · September 19, 2026
- Arc 1224 km · 766 m D+ · January 25, 2026
- Arc of Attrition - Arc 1224 km · 819 m D+ · January 25, 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 — Arc of Attrition - Arc 20K
Weather for Arc of Attrition - Arc 20K
The weather for Arc of Attrition - Arc 20K 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 Arc of Attrition - Arc 20K, hour by hour on the courseFrequently asked questions
How many checkpoints?
Arc of Attrition - Arc 20K has 2 checkpoints: 2 water points. Details are in the two tables above.
What's the longest segment without aid?
The one leading to Finish / Perranporth Airfield: 12.5 km and 442 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?
Arc of Attrition - Arc 20K is 22 km long with 722 m of elevation gain.
How long to finish?
With a UTMB Index of 600 (average runner), the estimated time is around 2h16 for Arc of Attrition - Arc 20K.
What's the weather forecast?
The weather for Arc of Attrition - Arc 20K 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 Arc of Attrition - Arc 20K?
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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