The mercury might have nudged 20 degrees in Wollongong on Tuesday, but daytime temperatures will struggle to just the mid-teens across the region for the rest of the week.

The real chill will be felt overnight, as minimums dip to as low as 3 degrees in Albion Park for three consecutive nights from Thursday. 

Overnight lows on the coast will also take a dive - Monday night's recorded minimum of 12.4 degrees will suddenly become just 9 degrees on Tuesday night, then 8 degrees for the rest of the week.

Twin fronts are responsible for the delivery of a large cold air mass over south-eastern Australia.

The first of the fronts should arrive on Thursday and the other on Sunday, making conditions in the region feel cold for the better part of a week, Kim Westcott, a meteorologist with Weatherzone, said.

The cold fronts, though, are unlikely to bring much in the way of fresh snow to key alpine resorts in NSW and Victoria desperate for more of the white stuff.