You'd be forgiven for thinking we'd jumped straight into summer with the mercury to rise to 26 degrees in the Illawarra.
Albion Park is set to have the warmest day at 26 degrees on Thursday, September 7. That's five degrees above the mean maximum for the month of 21.3.
In Bellambi the mercury will soar to 24 (mean maximum for September is 20.1) and Kiama will hit 23 degrees (mean maximum is 19.9).
Predictions may be for a warm day, but it's far from the hottest September day on record.
In September 2017 Albion Park soared to 34.4 degrees, in 2008 Bellambi reached 33 degrees, and the hottest September day on record for Kiama was in 2014 when the temperature peaked at 33.4.
Weatherzone meteorologist Maryam Al-Ansari said hot inland air is the cause behind the unseasonably warm weather.
"We've got frontal systems passing the south-east and they're dragging all the warmth from Central Australia to the coast," she said.
"They're going to suck up all the heat from Central Australia."
Temperatures will drop by around eight degrees on Saturday.
We've got frontal systems passing the south-east and they're dragging all the warmth from Central Australia to the coast.- Weatherzone meteorologist Maryam Al-Ansari
"From Friday and into the weekend we're going to get colder weather, but it's just more around the spring average," Ms Al-Ansari said.
"The evening between Saturday and Sunday will drop below 10 degrees."
The Illawarra is in for a hotter than average spring in 2023 following a warm winter which delivered record-breaking temperatures.
Meanwhile, firefighters are concerned about high forest fuel loads in the region, and the lack of hazard reduction burns conducted during the cooler months.
They have waned the community to expect smoke and traffic delays from Friday, September 8 as they undertake a significant hazard reduction burn north of Wollongong.