Can you breathe at 25,000 ft?
Can you breathe at 25,000 ft? At 25,000 feet the average EPT is 3 to 5 minutes. After about 20 minutes without supplemental oxygen, you will be pronounced dead.
Why is it so cold at 35000 feet?
Air itself is constantly in motion; it will often rise toward the sky. But, any air that rises will expand and cool, as it encounters progressively lower atmospheric pressure (explained further in the next section). The upshot is that the air outside a plane will be much colder than at ground level.