The North Island shivered in single digits after clear skies overnight but the south stayed snug under a blanket of cloud.
The central North Island will wake up to frosts this morning, as Waiouru hit 0C and National Park Village 1C.
Hamilton got down to 2C and even Auckland had a chilly start to the day at 8C.
Apart from the chilly start, fine conditions are forecast today and through the weekend across the North Island.
The South Island is in for a similar dose of sunny weather, only the West Coast getting a bit of rain as a front moves in tomorrow.
Today was a forecast of two halves, MetService forecaster Tuporo Marsters said.
"In the South Island high cloud in the morning will clear for a fine afternoon, while in the North Island it will be fine all morning until a little high cloud in the afternoon."
Light west to southerly winds are forecast across the country, and temperatures will be in the late teens to 20C, thanks to a big ridge of high pressure over the country.
Auckland and its northern neighbours Whangarei and Tauranga are in for highs of 19C.
Similar temperatures and relatively fine conditions are forecast across the rest of the North Island, where Wellington on 16C will be the coolest of the main centres.
The South Island is in for a relatively settled day on both coasts, with light winds and temperatures in the late teens. Even Invercargill will get a slice of decent weather, with fine and sunny conditions and a high of 18C forecast.
Temperatures in the south did not get as cold as the north overnight, thanks to a blanket of cloud.
Tomorrow northerlies pick up over the South Island as a front moves in, bringing rain to the West Coast. Rain could get heavy about Fiordland and south Westland on Saturday, and northern Westland and Buller during late Saturday and early Sunday.
The east will remain relatively fine, sheltered by the Southern Alps, but may get gusty northwesterly winds.
The ridge of high pressure will stick around over the North Island ensuring a warm, fine day for most parts tomorrow.
The weakening front will start to move over the North Island Sunday, bringing rain to parts and showers over the South Island.
A trough is then expected to move east across the lower South Island late Sunday, bringing a period of strong westerlies to the far south during Monday.
On Tuesday, another front is forecast to move northeast across southern and central New Zealand, preceded by strong northwesterlies and westerlies. There could be heavy rain about Fiordland and south Westland.
Periods of rain are expected about western parts of the South Island and lower North Island with these fronts.
Whangarei Cloudy periods. Light winds. 19C high, 11C overnight.
Auckland Fine spells, a few showers developing. Northwesterly turning southwest. 19C high. 9C overnight.
Hamilton Fine, but cloudy periods developing afternoon. Light winds. 18C high, 6C overnight.
Tauranga Fine. Light winds. 19C high, 10C overnight.
New Plymouth Fine with high cloud. Light winds. 17C high, 9C overnight.
Napier Cloudy periods, but long afternoon fine breaks. Light winds. 17C high, 7C overnight.
Wellington Fine with high cloud. Northerly breezes. 16C high, 10C overnight.
Nelson Cloudy periods. Light winds. 17C high, 11C overnight.
Christchurch Fine, apart from low cloud morning and evening. Northeast, strengthening afternoon. 15C high, 6C overnight.
Dunedin High cloud this morning and low cloud from evening, otherwise fine. Northeast developing morning. 17C high, 9C overnight.