Temperatures to plummet to near zero this weekend

It's time to break out the hot water bottle and fire up the wood burner for parts of the country.

Temperatures will plunge to near freezing this weekend as a cold snap rolls across the South Island.

Southerlies will blast the South Island with temperatures dropping significantly behind it - and we could face our first frost of the year on Saturday.

"A cold night is on the way on Friday night/Saturday morning with the high 'locking in' the brief cold snap," Weather Watch says.

"Air temperatures indicate we're on the cusp of frosts for the first time in 2018 with overnight lows dropping to just 1 or 2 degrees in Southland and some parts of Otago and the high country of Canterbury."

By Sunday the warm westerlies should return - thanks to the giant Southern Ocean storm.

"It's yet another example of Autumn's weather pattern being here - we're seeing a mix of warm to hot days and then some brief cold changes," Weather Watch says.

The North Island will stay warm, however, with the lowest temperatures hovering around 6degC in the centre at around 7am.