How does snow fall when temperatures are above freezing?
Snow forms when the atmospheric temperature is at or below freezing (0 Celsius or 32 Farenheit) and there is a minimum amount of moisture in the air. If the ground temperature is at or below freezing, of course the snow will reach the ground. However, the snow can still reach the ground when the ground temperature is above freezing if the conditions are just right. In this case, snowflakes will begin to melt as they reach this warmer temperature layer; the melting creates evaporative cooling which cools the air immediately around the snow flake. This cooling retards melting. As a general rule, though, snow will not form if the ground temperature is 5 degrees Celsius (41 degrees Fahrenheit).
