Rug up NZ! Whangarei shivers through coldest May morning in 42 years, South Island towns hit -6 and there's more on the way

Whangarei has shivered through its coldest May night in 42 years while two Otago towns experienced the coldest temperature of the year so far last night.

Temperatures in Ranfurly and Middlemarch hit -6 degrees, the coldest temperature recorded in New Zealand since last September.

Whangarei reached 0.8 degrees this morning, its coldest temperature in May since 1976 while Auckland, Hamilton, and Thames were all colder than Christchurch and Dunedin last night.

Up until yesterday, the normally sub-tropical Whangarei was on track for its fourth-warmest May on record.

NIWA meteorologist Ben Noll is warning tonight could be even colder across the country, with Whangarei potentially breaking its record for the coldest May temperature - currently 0.6 degrees.

He says the current cold snap is not an indicator that winter will be particularly frigid and feature record-breaking cold temperatures.

Mr Noll says New Zealand is currently in weather limbo, which will mean more variable weather.  

"For months we'd had a La Nina weather pattern which brings more warm northerly winds our way. Then it was like the rug was pulled out from underneath this global climate driver and we got something completely different.

"Mother Nature dances to the left, dances to the right and then takes a misstep – we're seeing it all at the moment."