Millions of Australians have sweltered through sizzling temperatures but relief is in sight with the mercury to drop for those on the southeast coast.
Melburnians baked on Monday, with the Bureau of Meteorology reporting a top of 37C.
Hot weather stayed consistent across large parts of the state, with Geelong reaching 38C and Bendigo hitting 35C.
An extreme fire danger rating is in place for the southwest region of Victoria until Monday night, with emergency crews on high alert.
Tuesday will bring a significant cool change across the state with Melbourne expected to peak at 25C.
Temperatures will range from 24C in Ballarat to 33C in Bendigo.
Adelaide sweltered through Monday, with the city's heat peaking at 38C after an uncomfortable overnight minimum of 27C.
Hot conditions in the high 30s and low 40s were forecast for most regional areas in South Australia, with a total fire ban widely declared.
Tuesday and Wednesday will bring some relief in the state's capital with a top of 33C is expected on both days.
Residents were told to evacuate as an out-of-control bushfire burned in Highbury in the Adelaide Hills.
The 2.5 hectare blaze was contained by fire services on Monday afternoon.
The bureau warned the conditions will persist in parts of SA, Victoria, NSW and Tasmania until Wednesday.
Hobart broke a record for its stifling Saturday night, with a minimum temperature of 24C beating out a previous record of 21.1C.
The warmer weather, roughly 10 to 15C than average is caused by a high-pressure system sitting in the Tasman Sea that directs hot northerly winds over southeastAustralia.
The temperature peaked at 36.9C in Melbourne late on Sunday, with Avalon recording 40C and Geelong 39.6C.
It followed a record-breaking Saturday night in the Victorian capital, with the mercury hovering about 30C until Sunday morning, when it dropped to 27.3C - toppling the previous March record-high minimum temperature of 26.5C in 2013.
The Bureau of Meteorology says those "blocking high-pressure systems" also prevent cold fronts being able to sweep across the southern parts of the country and flush away the heat.
"A southerly change is expected to move through early on Tuesday, giving the southern states some reprieve but it won't be until Wednesday or Thursday that a colder air mass will push in and bring those temperatures down," senior meteorologist Sarah Scully told ABC News.
Extreme conditions over the weekend forced event organisers to cancel some outdoor festivals and parades.
