Snow

Precipitation will fall as snow when the air temperature is below 2°C. Although you would expect the falling snow to melt as soon as the temperature rises above freezing, 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. Individual ice crystals and snowflakes can be the shape of prisms, plates or stars - but all have six sides.

• Thirty centimetres of fresh fallen snow has about the same water equivalent as 25 mm of rainfall.
• If rain falls continuously through air with a temperature as high as 6°C, it may cause the air temperature to fall low enough for the rain to turn to snow. This is due to latent heat being absorbed by the evaporation of water vapour from the raindrops as they fall, leading to the reduction in temperature.