Kiwis across the country are trying to thaw out after Auckland, Wellington, Christchurch, Hamilton and Tauranga all recorded their coldest nights for the year.
Auckland dropped to 1.4degC on Sunday morning, its coldest temperature in two years, MetService says.
The freeze was even more bitter in the city's suburbs as Māngere and Western Springs recorded temperatures of 0.4degC and -1.1degC.
Mt Cook was the country's coldest spot with -13.3degC, while Turangi in the North Island fell to -6.4degC at 6am on Sunday, its lowest temperature since July 2012.
Hamilton had its coldest morning in five years, recording a minimum of -4.4degC, while Christchurch hit -5degC, Tauranga zero and Wellington 3degC.
Dunedin dropped to zero, but that was not the city's coldest night this year after temperatures fell to -5.2degC on June 29, according to MetService.
But spare a thought for residents of tiny South Island town Tekapo where the temperature did not climb above zero at any point on Friday.
Instead, the town hit a high of -0.4degC and a low under -10degC.
Meanwhile, Fiordland and the West Coast are expecting heavy rain on Monday morning, with MetService issuing a severe weather warning.
Up to 100mm could fall on parts of Fiordland by 6pm Monday, while up to 120mm could hit the Westland ranges.