Today Auckland is set to reach a humid 26C before dipping to a balmy 19C overnight. Humidity was already at an uncomfortable 94 per cent by 8am.
In Tauranga residents are in for an equally challenging night, going from 23C in the day to 20C overnight. Napier goes from a sweltering 28C to 21C overnight.
In what MetService is describing as a "wet and windy interlude" the settled weather enjoyed over the Waitangi long weekend is being replaced with rainy days and humid nights as a front tracks up the country today and tomorrow.
The heaviest falls are reserved for Westland, Buller and Fiordland where a number of heavy rain warnings and watches are in place. However, Otago and South Canterbury are also likely to get a decent soaking, according to the forecaster.
On Tuesday, many North Island locations will be the hottest spots in the country, with Masterton, Palmerston North, Whanganui, Napier and Hamilton all rising to 27C and Hastings and Gisborne hitting 28C.
MetService says the sticky spell is expected to be broken by Thursday when southwesterlies bring cool relief and return the country to settled weather for Friday.