WA is set to swelter and Perth is forecast to have its hottest day in six years as heatwave conditions sweep the State.
Perth is forecast to hit 43C on Saturday, its hottest day since the mercury peaked at 44.2C in December 2007, and temperatures in many regional towns are expected to be in the high 40s for days.
But the Weather Bureau is predicting the State's record high of 50.5C, set in the Pilbara town of Mardie in 1998, will live to see another day.
That is despite temperatures in the Pilbara town of Onslow hitting 48.7C yesterday and 49C predicted for Emu Creek today.
The Australian high of 50.7C was set in South Australia in 1960.
The bureau yesterday warned of severe to extreme heatwave conditions as it rolled out a new heatwave warning service.
The heatwave, caused by a super-heated air mass moving through the State, will intensify in the Kimberley today and begin to take its toll in the South West, including Perth.
A heatwave is defined as three or more days with unusually high maximum and minimum temperatures.
Neil Bennett, from the bureau, said the heatwave was "quite significant" and the bureau would be watching some towns, including Merredin in the Central Wheatbelt and Lake Grace in the Eastern Wheatbelt.
News of the heatwave prompted warnings for people to avoid the sun in the heat of the day and stay hydrated to avoid heat stress.
The Health Department warns that heat stress can threaten a body's ability to function.
Australian Medical Association WA president Richard Choong said people should avoid going out in the sun unless it was necessary and be sure to wear a hat and sunscreen if they did.
He said heat stroke, which was stage three on the heat stress scale and often signalled by confusion, dry skin and a swollen tongue, could be life threatening.
Transperth is expected to put heat restrictions in place at the weekend if Perth hits its forecast maximums.
Shane Sercombe was on the Swan River yesterday, enjoying a spot of wake boarding.
Mr Sercombe's home town is Marble Bar - often referred to as Australia's hottest town because it set a world record between 1923 and 1924 of the most consecutive days above 100F (37.8C).
Well-accustomed to temperatures in the high 40s, Mr Sercombe said he was undaunted by the prospect of a 43C weekend.
"I live up there on a cattle station so I'm used to the hot weather," he said.
"You get used to it."