Heatwave conditions across South Australia last week are set to return, with a high-pressure weather system forecast to bring sweltering conditions on the weekend.
The Bureau of Meteorology says the air mass that brought temperatures in the mid-40s to some regional centres last week did not dissipate
"It has been going all this time through the north of the state and moved to WA, before re-emerging in SA," the bureau's regional director John Nairn said on Wednesday.
"It was a very shallow summertime change, in fact, it really didn't make us cool it just knocked the top off the temperatures."
Adelaide is forecast to have a top temperature of 38C for Australia Day on Friday before the mercury hits 42C on both Saturday and Sunday.
The State Emergency Service is encouraging all South Australians participating in sporting events and festivals over the long weekend to be proactive and keep themselves safe.
"We do know that this event will have a very similar severe heat factor to last week's conditions," SES chief officer Chris Beattie.
Last week's hot blast resulted in 150 people going to hospitals over the three days with another 40 people admitted for specific heat-related illnesses, SA Health spokesman Paddy Phillips said.
"SA Health really wants to remind people to stay cool, hydrated and safe over the long weekend," Professor Phillips said.
