In a statement, MetService said the calm and frosty weather would continue well into next week - but some brief showers would fall as a weather system moved up the country on Friday and Saturday.
Bitterly cold temperatures were felt on Thursday morning, with Mount Cook Airport recording its coldest temperature of the year so far at -7.1C.
Friday is expected to be much the same, with sub-zero temperatures forecast for many parts of both the North and South islands.
MetService said Taumarunui, Christchurch, and Wānaka could wake up to -3C.
Meteorologist Mmathapelo Makgabutlane said sunny skies would help warm up places during the day but a "chilly southwesterly wind means daytime temperatures will remain noticeably cool, even in normally temperate places like Northland".
Makgabutlane said a ridge of high pressure would be seen next week and stick around for several days.
"This means mostly settled and bright weather ahead, great timing for school holidays. However, the possibility of low cloud or fog settling into inland valleys, which may linger for a little while, should not be discounted."
There are currently no severe weather warnings in place.
