Why is the temperature low on the mountain?

A mountain is eager to radiate much more heat than its surroundings. So its temperature is very low.

On the plain, a piece of land gets the same radiant heat from its surroundings, so it can only radiate heat to the sky. This has caused its heat dissipation ability to be inferior to that of mountain peaks.

This is also the reason why the snow line of Independence Peak is always lower than that of other mountains in the same situation. Because independent peaks can radiate heat to the surroundings and overhead, and continuous mountains will also be radiated by other mountains, so the heat is saved a lot.

As for solar radiation, there must be more on the mountain than on the ground. However, because the heat dissipation capacity of mountain peaks is much greater than that of the ground, no amount of solar radiation can change the temperature difference. For snow-covered peaks, the actual solar radiation is lower than the ground because of its strong reflection of sunlight.