Altitude and oxygen
Lo Manthang: altitude and oxygen
Lo Manthang stands at 12,500 ft (3,810 m) above sea level. The air pressure there is about 632 hPa against 1,013 hPa at sea level, so a breath holds roughly 62% of the oxygen the same breath holds at the coast — the equivalent of breathing 13% oxygen instead of 20.9%. Air is still 20.9% oxygen up there; there is simply less air. In the standard atmosphere the temperature at that height is -10 °C (14 °F), which is a modelled figure rather than a forecast — a clear Himalayan morning is routinely colder.
- Elevation
- 12,500 ft
- Effective oxygen
- 13%
- Air pressure
- 632 hPa
- Standard temperature
- -10 °C
3,810 m above sea level.
What sea-level air would have to contain to match one breath here.
Standard atmosphere, against 1,013 hPa at sea level.
14 °F in the standard atmosphere — modelled, not forecast.
One breath here against one at the coast
Sea level
100%
20.9% oxygen at 1,013 hPa — the reference.
Lo Manthang
62%
Still 20.9% oxygen, at 632 hPa. The mixture is unchanged; there is less air holding it.
Flights that land here are on the ground for about 90 minutes. That is a published figure, and it is short by design — a helicopter tour reaches this height in minutes rather than the days a trek takes.
These figures describe the air, not anybody’s response to it. How a person is affected by height depends on the person, on how fast they got there and on how long they stay — a helicopter reaches these altitudes in minutes, which is a different exposure from a trek that takes days. If you have a heart or lung condition, are pregnant, or are travelling with young children or elderly parents, speak to a doctor before you book and tell the operator when you do: several carry supplemental oxygen and all of them plan the ground time around who is on board. Pressure and temperature are from the International Standard Atmosphere, which is a model — the real morning at this height is frequently colder and thinner still.
Flying here
Routes that reach Lo Manthang
Every one of these is a journey certified operators quote on, with the ground time each publishes.
At this height the aircraft’s lift, not its seat count, decides who comes — check what can be lifted to Lo Manthang, or see how far and how long the flight is.
Asked about this site
Lo Manthang, in detail
- How high is Lo Manthang?
- Lo Manthang is 12,500 ft above sea level, which is 3,810 m. That figure is the surveyed elevation of the landing site itself rather than of the surrounding terrain, which is why it can differ from the height quoted for a nearby summit or village.
- How much oxygen is there at Lo Manthang?
- Air at Lo Manthang is 20.9% oxygen, exactly as it is at sea level, but at about 632 hPa rather than 1,013 hPa — so a breath holds roughly 62% of the oxygen the same breath holds at the coast. That is the equivalent of breathing 13% oxygen at sea level.
- How cold is it at Lo Manthang?
- In the International Standard Atmosphere the temperature at 3,810 m is -10 °C (14 °F). That is a modelled figure, not a forecast and not a measurement: a clear Himalayan morning at this height is routinely colder than the model, and wind makes it colder still on exposed ground.
- How long do helicopter flights stay on the ground at Lo Manthang?
- About 90 minutes, on the itineraries operators publish for the routes that land here. Ground time at height is kept deliberately short, and the exact figure is set on the day by the pilot against the weather, the aircraft's weight and who is on board.
Another site
Check a different landing site
Flying to Lo Manthang with someone who needs care?
Leave a number. A dispatcher rings back and plans the ground time, the oxygen and the landing around who is on board — the part of a Himalayan flight that gets decided on the phone rather than in a form.