Please answer my question about geography, thx!

This is because snow forms in the atmosphere, not at the ground surface.

Snow forms when the atmospheric temperature is at or below freezing and there is a minimum amount of moisture in the air (the exact level varies according to temperature).


Snow can fall even when surface temperatures are above freezing as long as atmospheric temperatures are below freezing and the air contains a minimum moisture level.


In this case, snowflakes will begin to melt as they reach the warmer temperature layer; the melting creates evaporative cooling which cools the air immediately around the snowflake. This cooling retards melting.

雪是在高空形成,
高空的氣溫達攝氏0度或以下, 雪才會形成,
下雪時, 地面的溫度未必低至攝氏0度,
但一般亦不會高於攝氏4度, 否則雪未到地面便會溶化