ADELAIDE’S weather again looks set to be scorched into the record books, as top temperatures of 40C or higher are forecast for four days in a row.

After a steamy night in which the mercury hovered around 30C, the temperature had already hit 36C at 9.30am. And by 1pm it had already hit the forecast maximum of 42C.

It was 42.6C just after 2.30pm.

Such an unbroken run of soaring forties in December has never been recorded in the city but, after today’s sizzling weather, and a high of 41.1C at 3.19pm yesterday, Friday is expected to reach 41C and Saturday, 42C.

Although similar four-day runs have been recorded in February, the current event would be the earliest in any summer since January 3-6, 1906.

Bureau of Meteorology senior forecaster Matt Collopy said that “four days greater than a record of 40C in Adelaide has never happened in December since records began in 1887”.

“We had to go right back to 1906 to see that the earliest we had these temperatures in summer was in January, it looks like we’ll break that one,” he said.

He said a slow-moving high-pressure system sitting over the Tasman Sea to the east of Australia was causing the extreme temperatures.

“The high hardly moves,” Mr Collopy said.

“There are other weak systems over the south of us, but they’re not bringing any southerly winds to relieve the hot conditions at the moment.

“The high is really stationary and it’s continuing to dominate the weather with a hot northerly airstream.”

But said there is some relief on the way on Saturday with a “cool” night-time change expected to drag Sunday’s maximum down to a more comfortable 30C.

“There is some variation in the timing of that change, but we believe it will come through around 9pm on Saturday night,” Mr Collopy said.

“Coastal areas will probably see cooler temperatures first as the cold front comes through off the southern ocean and brings up cold air from the south.

“For everyone else, by Sunday morning things will start to cool down and people will feel some relief.”

Not everyone’s prepared to wait for a cool-down, though, and many yesterday flocked to city beaches for a swim.

Former Adelaide resident Andrea Silverback, back for the summer from Melbourne, took her children Ruby, 10, and Axel, 1, to Henley so her children could play at the beach.

But it was the new water feature that took Axel’s attention.

“We’re used to the hot conditions and scorching heat in Adelaide because we used to live here and we come back every Christmas,” she said.

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“We were up early and there were lots of people at Henley, especially families.

“Going to the beach is a great way to spend a hot day as long as there is shade for the little ones.”

The heat caused practical problems for more than 500 people left without power across the city yesterday, with outages in the southern, northern and western suburbs.

SA Power Networks said crews worked quickly to restore power to homes.

While at the Adelaide Railway Station bottles of water were handed out to commuters.

Total fire bans have been declared in three of the state’s 15 districts on Thursday.

The Northwest Pastoral, Mount Lofty Ranges and Lower South East all face severe fire conditions.