Australians have been warned to check on vulnerable friends and family this weekend as parts of the country swelter through temperatures as high as 50C.
Residents of New South Wales, Victoria, South Australia, Western Australia and the Australian Capital Territory are already experiencing scorching temperatures.
The heatwave is being caused by a low pressure system that is moving from SA, through NSW and north Victoria and hitting the east coast, including Sydney.
It is also forecast to move north up the east coast to Brisbane in Queensland.
Bureau of Meteorology forecaster Jonathan How said the heatwave will ‘impact millions of people and create dangerous fire weather conditions for multiple states’.
Fire weather warnings have been now been issued for NSW, Victoria, SA and WA.
Sydneysiders flocked to Bondi Beach in September and they are expected to do so again this weekend as the maximum is forecast to reach 39 degrees in the NSW capital
In addition to causing bushfires, Mr How warned the heatwave itself will be ‘a huge silent killer’ as it causes hyperthermia, dehydration and skin cancer.
‘The hot days and warm nights will make it difficult to recover, especially for vulnerable people,’ Mr How said.
‘People are hospitalised and it’s really dangerous so it’s important to take note of the heat and be careful.
‘Heatwaves are normal for this time of year but the temperatures and duration of this event will be exceptional.’
Heatwaves have killed more people than cyclones, flooding and bushfires combined in Australia in the last 100 years, making it the country’s biggest killer.
Sydney will reach a maximum of 39 degrees on Saturday, making it the hottest capital city in the country – with a ‘very high’ fire danger warning in place.
Beachgoers are advised to use sun protection as the UV index will be ‘extreme’ at 11, which will be very damaging for skin.
The 39-degree maximum will continue on Sunday as a low pressure system brings the muggy weather across from South Australia through NSW to the east coast.

A runner at Bondi Beach at sunrise. People who want to exercise outdoors have been advised to do so at dusk or dawn or even at night for slightly cooler temperatures
The temperature will drop to 24C on Monday before jumping back up to 29C on Tuesday and remaining the mid 20s for the rest of the week.
‘On Saturday, temperatures will climb to 47 degrees through inland South Australia and above 40 degrees along the Murray but Southern Victoria will be spared the worst of it,’ Mr How said.
‘A gusty cool change will extend east through the day, hitting the high 30s through Sydney and western Brisbane on Sunday.’
Adelaide is not far behind Sydney with a maximum of 37 degrees on Saturday – but rain developing in the late afternoon may provide some reprieve.
SA towns such as Coober Pedy, Port Augusta, Roxby Downs, Moomba and Renmark will all reach maximums of 47 degrees on Saturday.
Inland NSW towns Broken Hill, Ivanhoe and Wicannia will see temperatures in the low to mid 40s on Saturday before the weather moves to the coast on Sunday.

A low pressure system will move from South Australia, through NSW and north Victoria and to the east coast, including Sydney, before moving north to Brisbane in Queensland
Mildura in regional Victoria is expected to reach 45C while Horsham and Bendigo in the state’s north will reach the high 30s.
Melbourne will largely escape the heat with a pleasant maximum of 28 degrees.
Canberra will have a maximum temperature of 34 degrees on Saturday – a figure that matches Darwin in the Northern Territory, which will also reach 34 degrees.
‘On Saturday, severe to extreme fire dangers will continue in South Australia and extend into Northern Victoria and in parts of NSW,’ Mr How said.
‘And on Sunday, very high to severe fire dangers are forecast for eastern NSW and southeast Queensland.’
‘People should also be aware of severe heatwave conditions over inland parts, reaching the coast over the weekend and intensifying to extreme levels for northeast NSW and southeast Queensland into next week.’