Ultra Running Hub Chiang Mai City, Thailand · Saturday, November 21, 2026
Fixed Distance 50K
AIA One Billion Trail
66 days away
50 km Distance
2,406 m Climbing
6.1 Grit · Hardcore
What the course asks
Climbing rate 48 m / km
Mountain. Significant climbing. Steep sections will require power hiking.
Time limit 17 hours
20:24 min/km average. Generous. Walkable throughout for most of the field. Among the most forgiving 50K cut-offs we track. Measured against 1007 races of the same distance. Cut-off calculator →
Field size ~23 Small. Long stretches with nobody in sight.
DUV results for the 2025 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Typical conditions, November
Daytime high 25°C
Night low 16°C
Rainfall Mostly dry
Daylight 11 h 11 m of light
Regional 2001-2020 average for November — NASA POWER, grid elevation 759 m. Not a forecast.
The Aid Station
Course-specific beta from the community
This is a mountain course. Poles are highly recommended for the sustained climbs.
With trail terrain, choose a shoe with moderate cushioning for optimal performance.
Gear for this race
Chosen for 50 km of trail with 2,406 m of ascent.
- Trail Running Shoes48 m of climb per kilometre — grip and rock protection before cushioning.
- Race Nutrition50 km of self-supported fuelling between aid stations.
- Hydration VestsPole attachment and chest-strap stability on steep ground.
- Trekking Poles2,406 m of ascent to walk up.
- HeadlampsA 17 h limit puts you out there after dark.
Similar races
Other 50K trail ultras, closest in distance first.