Australian Weather Calendar: December 2017

December photograph by Cathryn Vasseleu

Frost, fog and snow are Leanne Osmond's favourite things to photograph; so when she visited St Marys on Tasmania's northeast coast in July 2014, she fell in love with the scenery–and moved to Tasmania!

Frost is a deposit of soft white ice crystals or frozen dewdrops, formed when the surface temperature falls below freezing point. Frost formation is affected by cloud coverage, humidity, surface winds, topography and location. In Australia, frost is more likely to form under a clear sky, with low humidity and light surface winds.

In these conditions, when observed air temperatures (measured in a Stevenson screen about 1.2 m above the ground) drop to 2.2 °C, the ground surface is approaching 0 °C and frost is possible.