Why do the highest mountains have a permanent snow line?

Answer 1

Its not the highest mountains that have a permanent snowline, its where they are located on earth that dictates it. The snow line varies by what country you are in. What matters is temperature, which coincidentally does decrease by 1 degree Celsius every 100m in elevation (height).

Answer 2

Temperature decreases as you get higher. If you get high enough, the average temperature is below 0°C most of the year, and the few days in summer which are above 0°C are not enough to melt all the snow which fell during the long winter.
The snow stays there permanently until there is enough to slowly slide down the mountain under its own weight. This is called a glacier.

Temperature also decreases as you get nearer the poles. The height above which glaciers form is highest at the equator, and decreases as you get to the poles. For example, Mount Kilimanjaro is on the equator and has a glacier on its 5895 metre summit. In the Alps, Glaciers start at about 3000m. In the Antarctic, glaciers go down to sea level.

Answer 3

because of precipitation and cold weather when it rains it freezes and turns int snow

Answer 4

the temperature decreases 1degree Celsius for every 1ooo mt .so precipitation will occur in form of snow. so high mountains have snow on top