For snow to reach the ground the air temperature must be no more than 2°C. One would expect the falling snow to melt as soon as the temperature rises above freezing, but this is not so. As the melting process begins, the air around the snowflake is cooled. At temperatures above 2°C the snowflake will melt to become 'sleet' or rain. In this country, the heaviest falls of snow tend to occur when the air temperature is between zero and 2°C.