A resident in Waco, Texas clears snow as the oil-rich state struggles to cope with a historic cold snap
A resident in Waco, Texas clears snow as the oil-rich state struggles to cope with a historic cold snap AFP / Matthew Busch

Parts of Victoria and South Australia are under advisories due to sub-zero temperatures brought on by the freezing air from the Southern Ocean, and there is also a warning of more extreme weather to come.

With effect from Monday morning, the Bureau has issued frost warnings for Victoria and South Australia, alerting locals to the impending cold weather. People in the affected areas are urged to prepare for a protracted period of exceptionally cold weather, with temperatures anticipated to drop as much as 8C below the seasonal average, 7 News reported.

"Both maximum and minimum temperatures will be below average at times this week in all state capitals," senior meteorologist Christie Johnson told 7NEWS.com.au.

"The lowest maximum and minimum temperatures are forecast for Canberra, with an overnight minimum of -4C forecast for (Tuesday) morning, and a maximum of just 10C forecast for Wednesday.

Additionally, the BOM has issued frost warnings for parts of Victoria and South Australia, which go into force Monday morning, per News.co.au.

A representative for the bureau explained that the chilly southerly winds in southeast Australia originate from the Southern Ocean and are caused by a low-pressure system in the Tasman Sea.

"This is causing daytime and night time temperatures to be below average for much of Tasmania, Victoria, NSW, ACT and southern Queensland," the spokesperson said.

"Cloud coverage cleared across much of the southeast over the weekend. Due to these clear skies, the temperature overnight cooled rapidly, leading to a chilly, and even frosty start for some places today.

"While the afternoon maximum temperatures may rise a few degrees, the cool nights are here to stay all week, possibly even colder for many areas on Tuesday morning and again on Wednesday morning," the spokesperson said.

"Within our forecast period (the next seven days), there is no significant change in the weather pattern that will bring warmer weather. There may be some variation from day to day, particularly due to changes in the cloud cover."

7NEWS According to Sydney weather anchor Angie Asimus, the chilly spell is occurring just a few days before the Winter Solstice.

Six states are seeing below-freezing temperatures as we approach Friday, June 21, the shortest day of the year, the speaker stated.

Monday's low temperatures in southern Australia were 0.8°C in Mildura, -0.6°C in Nuriootpa, and -0.7°C in Mudgee. At Falls Creek, wind chills of -10.5°C were recorded in alpine regions. Strong winds caused by a Tasman low surged five meters or more over the east coast, posing a serious risk of major beach erosion at Lord Howe Island.