Temperatures were expected to plunge below zero in some parts of the Illawarra early today with more freezing weather forecast for tonight.
The Bureau of Meteorology has predicted severe frosts in the hinterland and winds of up to 45km/h across the Illawarra, leaving no doubt that winter has arrived.
Daytime temperatures in Wollongong will struggle to push past 15 degrees today and tomorrow, although the bitterly cold winds will make it feel two to three degrees colder.
A relatively balmy top of 17 degrees is forecast for Friday.
Meteorologists say the collision of a low-pressure system east of Tasmania and a high pressure system south of Western Australia is dragging frigid air from the Antarctic north over south-eastern Australia.
Temperatures below freezing are not unheard of in the Illawarra, although they are rare, with just a handful recorded in recent decades.