The weather gods have gone crazy, with last week's record-breaking heat followed by snowfalls today on the Victorian Alps.
There was a light dusting of snow on the mountains Monday night as temperatures plunged below zero. Heavier falls are expected Tuesday night. Mt Baw Baw could get up to 20 centimetres of snow.
"Overnight not a huge amount of snow has fallen – it's just a dusting," said Bureau of Meteorology duty forecaster Michael Efron.
"But overnight tonight the cold front will be a fair bit stronger. Baw Baw could get 10 to 20cms ... because it's further south. There'll be not so much snow further north, probably 5 or 10cms.
"It's quite a decent fall for this time of year."
Mt Hotham reached minus 1.5 degrees overnight, Mt Buller minus 1.2 and Mt Baw Baw minus 1.1 and further sub-zero temperatures are expected Tuesday night.
Melbourne's overnight low was 12 and today's top is expected to be 18. The average December high and low for Melbourne is 24.2 and 12.9 degrees respectively.
Mr Efron said summer snow fell on average every couple of years, most recently on January 11 when it snowed in Mt Buller.
"It's not uncommon. We can get snow any time of year in Victoria. The waters to the south of the continent are still pretty cold. All you need is a front to come up from a fair way south and you can get snow."
Melbourne's high temperatures on Wednesday and Thursday are forecast to be 19 and 23, with the heat returning on Friday with 31.