Waiouru in the central North Island plummeted to a chilly -7°C degrees, Taupo went to -5°C, while Rotorua and Hamilton dipped to -3°C, and Whenuapai, in the Waitakere Ranges, was as low as -2°C.
Auckland motorists were faced with the unfamiliar sight of ice on car windscreens this morning as the temperature fell to an unusual 1°C.
That was lower still than Saturday night's 1.4°C - the city's coldest temperature in two years.
Whangarei managed a record of sorts with its 8th coldest morning since 1967, according to NIWA.