Residents in outer Melbourne are waking to their coldest morning of the year so far, with a forecast minimum of zero degrees.
While the mercury in the centre of the city struggled to just over 1 degree, in western and southwestern suburbs it was freezing.
Elsewhere in Victoria, temperatures in Horsham, Bendigo, Ballarat, Geelong and the Mornington Peninsula dropped to between –1 degrees and -3 degrees.
Residents in Tasmania, South Australia and southern Western Australia will also be feeling the chill early today, with the mercury stuck at single digits and widespread frost, according to the Bureau of Meteorology.
Melbourne could be in for a week-long run of mornings at or below 5 degrees. If this were to happen it would be the first time since June 2013, the coldest week in 11 years.
The cold mornings are being caused by a combination of a cold air mass, clear skies, light winds and a strengthening high pressure system over southern Australia.
These conditions are setting new low temperature records.
A weather station near the small town of Liawenee in Tasmania recorded a minimum temperature of -10.8 degrees shortly after 7.30am yesterday.
Not only was this the coldest place in the country yesterday, but it was also the equal lowest temperature recorded anywhere in Australia in two years.
This high pressure system will continue to cause bitterly cold temperatures across southeastern Australia over the next few mornings, forecasters say.