Gale-force winds and heavy rain are expected to hit the North Island midweek, replacing mainly fine conditions over the weekend.
A deepening sub-tropical low is forecast to move over the North Island from the north on Monday before slowly moving off to the southeast of the country.
Through Tuesday and Wednesday the low was expected to move southwards across the North Island, bringing southeast gales and heavy rain.
The MetService has issued severe weather warnings and watches.
On Tuesday there is a high chance that rainfall could reach warning levels over Gisborne and northern Hawke's Bay.
There is also a 40 per cent chance of gales becoming severe about the "western slopes from East Cape to Taihape and Taranaki".
"On Thursday, the low should move away to the southeast, bringing more settled weather," the MetService said.
A heavy rain watch is in place for Northland, Auckland, Coromandel Peninsula, Bay of Plenty including Rotorua and the Kaimai Range from 2pm Monday to early morning Tuesday.
A strong wind watch is in place for Auckland, Coromandel Peninsula and the Bay of Plenty from Monday afternoon to Tuesday morning.
May was a record-breaking month for the South Island as temperatures in several areas of Otago and Southland stooped to new lows.
Lauder in Central Otago broke its May daily maximum air temperature record when the mercury dropped to -2.6degC on May 31 - the lowest high since records began in 1924.
Niwa climate scientist Gregor Macara said the nationwide average temperature in May 2018 was 11.2degC (0.4degC above the 1981-2010 May average) and the autumn (March-May) nationwide average temperature was 13.8degC (0.6degC warmer than the 1981-2010 autumn average).