Extreme heat descended across western Sydney on Tuesday, with Sydney Olympic Park reaching 36.5C by 1pm.
The scorching temperatures sent thousands of people flocking to Bondi and other beaches including Pondi, or Penrith Beach in the western suburbs, to beat the heat.
If you couldn't get to Pondi there was always the world famous Bondi Beach in Sydney's east. (Mick Tsikas/AAP PHOTOS)
But there was sad news in Catherine Hill Bay, a coastal town south of Newcastle, where a 55-year-old man died after being pulled from the surf.
Penrith and Richmond hit maximums of 41.6C and 41.4C respectively ahead of a gusty cool change expected on Tuesday night.
That cool change could bring severe storms with damaging winds, large hail and possible flash flooding.
Temperatures pushed into the mid-40s in parts of NSW, Victoria, SA and Queensland on Monday, one of the hottest December days since 2019.
A slight reprieve is expected for NSW on Wednesday, with cooler conditions and showers forecast before returning to warmer conditions on Sunday.
Despite a cold front easing conditions in southeast Australia overnight, total fire bans remain in northwest Victoria and heatwave conditions are expected to linger for days in the NT and southern Queensland.
Total fire bans remain in Victoria where crews have tackled dozens of blazes. (Diego Fedele/AAP PHOTOS)
Extreme conditions persist in Victoria's Wimmera region after firefighters battled more than 40 grass and scrub fires in Cresswick near Ballarat, State Control Centre spokesman Luke Hegarty said.
Residents near the 200ha bushfire at Cresswick were told to evacuate on Monday night but the situation had improved enough for the warning level to be downgraded on Tuesday.
A 10-year-old boy died in Mooroopna in the state's north on Sunday after he became trapped in a boot during a game of hide and seek as temperatures reached 35C.
Temperatures did not surpass 30C anywhere in Victoria on Tuesday except for Mildura in the state's northwest.
Queensland's west and northwest faced another day of blistering heat after maximums of 43C and 43.4C were recorded in the outback towns of Mount Isa and Winton.
Brisbane, Mackay and Townsville could face heavy rain and flash flooding, with isolated downpours of up to 250mm forecast.
Downpours are forecast for Brisbane and other Queensland centres with the risk of flash flooding. (Darren England/AAP PHOTOS)
Insurers are urging Australians to prepare for the season ahead, with NRMA research noting 42 per cent of wild weather claims it receives arrive in summer, retail claims executive general manager Luke Gallagher said.
The data showed more than one in 10 Australians had returned from holidays to find their homes damaged by thunderstorms, hail, floods, wild winds or bushfire.
Heatwaves are expected to become hotter, longer and more frequent, according to Monash University associate professor Ailie Gallant.
"These are some really hot temperatures for mid-December that we haven't had in quite a few years," Dr Gallant told AAP, noting the increased fire risk.
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