Why is it colder as you go higher in altitude?

Question

(I realize that this can be inverse in some areas)

Answer 1

Actually the average air temperature decreases as you go up in the troposphere (bottom layer), increases as you go up in the stratosphere, decreases again in the mesosphere, and increases again in the thermosphere! Your question really pertains to the troposphere, of course. The main reason is that the Sun warms the ground, which in turn warms the air. So the air closest to the ground is the warmest. Air density and humidity play a role, too, but the warm ground is the most important part.

Answer 2

The air does become more compressed as you go higher in altidude but this also has to do with the saturation of the air as you increase in altidude, because the colder the air the less water it can hold. For every 1 km that you increase in altidude, the temperature decreases 10 degrees.

Answer 3

there is a relation between compression and temperature. more compression more temperature. for this reason if you go near sea side the air is more compressed than in the altitude and the tem. is more than in the mountain.