Aucklanders can expect a high of 16C and overnight low of 12C today. A shower or two is forecast in the City of Sails - as well as clouds - and some gusty southwesterly winds.
Gusts of up to 48km/h are forecast.
Tomorrow will bring some cloud in the morning, in Auckland, before breaking out into a fine day with southwest breezes.
A high of 18C is on the cards and even warmer temperatures are expected on Sunday, Monday and Tuesday - up to 21C.
The National Institute of Water and Atmospheric Research said high temperatures would surpass the 30C-mark, with the warmest readings set to be in the Bay of Plenty, Gisborne, Hawke's Bay, Wairarapa and Northland.
"The warmth will be spurred on by a hot air mass moving across the Tasman Sea from Australia, which has experienced ongoing, long-term drought conditions," he said.
WeatherWatch analyst Aaron Wilkinson said there is a risk of a shower along the east coast tomorrow morning before becoming mostly sunny in the afternoon.
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"[It is] mostly sunny for the rest of the North Island with some high cloud,'' he said.
"Mostly sunny for a majority of the South Island with some high cloud about - temperatures becoming warm for some areas."
Further north, around Northland and towards Whāngārei is fine today. Temperature highs in the area are even hotter - with highs of between 23C and 25C forecast from Sunday onwards.
Similar conditions are on the cards for areas including Tauranga and in and around Gisborne, where temperatures start to push up towards the late 20s to early 30s.
The ridge is due to move away to the east of the country on Monday and will make way for a front that will bring gloomy weather to Fiordland, before moving northwards across the South Island on Tuesday.
"There is low confidence of warning amounts of rain falling in Fiordland and Westland on Tuesday."
RECORD-BREAKING TEMPERATURES AHEAD:
Those in the South Island will be happy to know it will be sunny for the majority of places also - save for some high cloud.
The temperature highs, some reaching the 30C-mark, may even break some records this weekend or next week, according to Niwa.
Niwa forecaster Ben Noll said yesterday that much warmer-than-average teemperatures would spill on to the South Island tomorrow and continue through to Sunday and Monday.
"Maximum temperatures will eclipse 30C for the first time this spring in parts of the South Island - like Otago, Canterbury and Marlborough," he said.
"Some records may also tumble''.
Nelson has temperature highs of between 18C and 27C over the next few days, while Blenheim is getting ready for a scorcher Sunday, with a temperature high of 31C predicted.
Temperature highs of between 27C and 31C are due in other areas including in Queenstown and Dunedin.
