Saturday is predicted to be a 'very extreme heat' day, as metro areas won't see temperatures dip below 30C through the daytime.
While in Queensland, forecasters are predicting mammoth rainfall - the wettest in years.
"January 2023 could shape up to be the wettest single month for pockets of the Queensland coast since February 2021," Sky News Weather meteorologist Alison Osborne said.
Osborne said southern states of SA and Victoria will face humid air across the weekend.
"As that heat pulls over South Australia and into Victoria, it will be joined by very humid air off the northeast. This means it is going to feel rather tropical," Ms Osborne said.
"Saturday is going to be the day of very extreme heat and elevated fire dangers particularly in South Australia."
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