The mercury hung below zero degrees for more than 12 hours between Tuesday and Wednesday morning, according to the Bureau of Meteorology's Sean Carson.

Motorists will have to continue splashing and scaping their windscreens this week with the frosty, sub-zero temperatures set to continue until the weekend, with -4 degrees forecast as the minimum for Thursday, -1 degrees on Friday and -3 degrees on Saturday.

Mr Carson said the cool starts weren't unusual for early June, including -5 degrees on Tuesday, but Monday night's low of -7 degrees was quite rare.

"It's something we probably see an average of once every three weeks," Mr Carson said of Monday's minimum.

"This week has been pretty cold. What has been unique over the last two nights is it's been getting below zero between 7 and 8pm.

"With such prolonged times below zero there's been quite severe frost."

This week's chilly nights and early mornings come on the back of an August string of eight days at -5 degrees or colder including a minimum -8 degrees.

Mr Carson said the recent weather was the result of a cold front moving through the region from Monday morning, however, the days were slowly warming up in the lead up to a relatively mild long weekend.

"We'll have nice, warm afternoons with top temperatures of up to 16 degrees by Sunday and 15 degrees both Saturday and Monday; three to four degrees above average, so there's nice warm air moving across the region," Mr Carson said.

"It could actually get up to 18 degrees, potentially.

"We will get a bit of a breeze from Sunday afternoon, taking the edge off what will otherwise be quite a glorious weekend."

The week ahead also signals the beginning of El Nino conditions sweeping through the country.

"This is pretty typical - dry weather, cold frosty nights and warmer than average daytime temperatures," Mr Carson said.

"There's a chance of rain, a couple of showers at sunrise on Friday morning but probably only one or two millimetres. Otherwise it's dry, dry, dry."