After a relatively mild summer, authorities are warning of a potentially dangerous heatwave forecast for Victoria the weekend.
Sunday will be the hottest in the north-west with temperatures predicted to soar to around 44 degrees Celsius in Mildura as the heat begins to build.
A mass of hot air is being strengthened by a cyclone brewing off the West Australian coast.
"Monday will be the warmest day for much of Victoria including the Melbourne area," said Diana Eadie, from the Bureau of Meteorology.
"We're expecting the temperature to be around 41 or 42 degrees.
"We are going to see a large part of the state exceeding 40 degrees for the first time for many of those areas since January of last year."
What makes the conditions particularly dangerous is the overnight temperature.
Overnight Sunday and into Monday the temperature won't drop below 24 degrees, meaning people won't have a chance to recover between the hot days.
"This is more than just one hot day — it could potentially be very dangerous for people's health," Ms Eadie said
"Generally speaking it has been quite a mild summer thus far and that's why this particularly hot day is really going to take people by surprise."
Extreme heat kills more Australians each year than any natural disaster.
Forecast gusty cool change increases fire risk
A gusty cool change is expected in the latter part of Monday, leading to an elevated fire risk.
The fire danger in the north will be severe with hot, dry and windy conditions in central areas, forecaster Keris Arndt said.
"The northerlies are picking up during Monday especially — we have severe fire dangers in the north of the state," he said.
"[In] Melbourne and central parts there's generally still enough moisture around for it not to tick over to fire weather warning territory."
The heatwave is also expected to hit Adelaide with a forecast top of 39 degrees today and 41 on Sunday.
South Australians have been warned to be on high alert this weekend.
Drownings at Anglesea, Barwon Heads
A 58-year-old man died when the boat he was in overturned off Anglesea about 2:00pm.
Another man made it back to shore and raised the alarm.
Lifesavers attempted to revive the man but he died at the scene.
Police said the men were both wearing lifejackets but the conditions were too rough.
Another man was pulled from the water on Thirteenth beach at Barwon Heads after getting into difficulty about 5:00pm.
A boy and girl were assisted back to the shore while the man was winched from the water by a helicopter.
They will prepare a report for the coroner.
It has been one of the worst summers for drowning on record and Lifesaving Victoria is worried about the hot weather.
Forty people have drowned since July last year, with five deaths in seven days.
Dr Bernadette Matthews said thousands of children had missed out on swimming lessons during the lockdown and people should swim within their capabilities.
"If you're not a confident swimmer, head to one of our fantastic pools," she said.
"If you do go to a beach go to a patrolled location.
"If your kids are in the water, make sure you're in the water with them."
The Cancer Council said people should not rely on sunscreen alone to protect them.
They should use five types of protection — clothing, hats, shade and sunglasses as well as sunscreen.ABC