Three weeks into spring and fires are ravaging multiple states as temperatures hit record highs.
Fire danger zones are in place across the east coast with 64 fires burning across NSW, some threatening homes on the Queensland border and Sydney's western fringe.
In Tasmania, campers and residents were forced to sleep in their cars as a bushfire threatened a tourism hotspot on the state's east coast.
Extreme fire danger warnings are expected in southern parts of Queensland and into the vast outback Channel Country on Thursday and Friday as the heatwave moves north.
Unseasonably hot and dry conditions have left large parts of south-eastern Australia sweltering with maximum temperatures 10C to 15C above the September average.
A total fire ban remains in force for the Greater Sydney, Hunter and Upper Central West regions.
Nineteen blazes were yet to be contained as of 1.30pm on Wednesday with winds expected to worsen in the afternoon and evening, the Rural Fire Service said.
A catastrophic fire danger warning is current for the far south coast of NSW as residents fear a recurrence of the state's worst black summer of bushfires in 2019/20.
Temperatures in Sydney soared to 35.9C at the airport on Tuesday, breaking the previous high of 35.6C set for the month in 2000.
The spring heatwave continued on Wednesday with Penrith in Sydney's west hitting a maximum of 35.2C at 2.20pm.
But relief is in sight as a cold front is set to move across NSW from Wednesday evening, dropping temperatures to the low 20s for Thursday and into the weekend.
Miriam Bradbury from the Bureau of Meteorology said the wind change would sweep through south-eastern NSW and the Sydney area by early Thursday.
"We're going to see that heat really focusing in on Queensland," Ms Bradbury said.
"Temperatures across the state are going to push into the 30s for the most part - the high 30s across those parts of the northwest.
"By Friday, (the heat) will move into the Northern Territory as well, with even a 40C day on the forecast around the Gulf."
In the south of the country potentially damaging winds across parts of eastern Alpine Victoria and south-eastern NSW could bring down trees or powerlines.
A wildfire near Coles Bay Road at Friendly Beaches in Tasmania sparked an emergency warning on Tuesday afternoon and has since burned about 700 hectares fanned by strong winds.
It was downgraded to watch-and-act level on Wednesday, with authorities confident cooler conditions would help them get it under control.
The Bureau of Meteorology officially declared an El Nino weather event on Tuesday, which brings hot, dry weather and increases the risk of heat exhaustion and bushfires.
Extreme heat is one of the most direct and measurable shocks from climate change and one of the deadliest, according to the independent Climate Council.
A report released by the council on Wednesday found existing government targets leave Australia "barrelling towards catastrophe".
More Australians have died as a result of extreme heat than any other natural hazard, they said.
"We stand at the precipice. Once we cross those tipping points, we cannot return," co-author Lesley Hughes said.
Emissions from transport and heavy industry continue to rise, putting Australia on track for even more harmful levels of global warming, the Climate Council modelling shows.
Up to 250,000 Australian properties are at risk of coastal inundation under a rise of well over 2C by the end of the century.
Marine ecosystems would collapse and irreversible change in rainfall patterns globally would destroy food production.
"So it really doesn't get much more urgent than this - we've got to aim higher and go faster," Professor Hughes said.
