The country is in for a weather "rollercoaster" before temperatures rise into the 30s next week, a meteorologist says.

A cold front is approaching and expected to move up the country from Friday, bringing colder days and possible heavy rain in the South Island, National Institute of Water and Atmospheric Research's (NIWA) Chris Brandolino told Morning Report.

MetService has issued heavy rain watches for the ranges of Buller and Westland District from Friday.

Buller's watch is in place from 10am until 8pm, while Westland's is in place from 4am until 4pm.

Both have forecasts of heavy rain that may approach warning criteria. Westland could also see possible thunderstorms.

Meanwhile, a strong wind watch is in place for Wairarapa from Masterton southwards, Wellington and Marlborough Sounds from 1pm until 9pm on Friday.

Brandolino says warm weather will be experienced around the country on Thursday, particularly in the Bay of Plenty and Hawke's Bay, where temperatures will be in the upper 20s, approaching the 30s.

NIWA's Chris Brandolino. Photo: Chris Brandolino.

Auckland will be a "notch or two" cooler than it was on Wednesday - when a heat alert was issued by MetService - but it will still be warm.

The next two days will be a "rollercoaster" with showers and squally weather possible for the North Island.

The weather will be unsettled on Friday night and into Saturday, with a day or two of "unusually cool, brisk temepratures for this time of year".

But the rest of February is shaping up to be warm - but with cooler days in between, unlike January.

Brandolino told Morning Report Auckland had seen 22 days of temperatures above 25C in January.

That compared with the "bummer summer" in 2023, where Auckland saw just seven days above 25C.

Auckland will see "spikes" of hot weather in February but colder temperatures will be felt too, he says.

Warm air is coming from Australia next week, says Brandolino, which will set the country up for potentially high temperatures.

Monday, Tuesday, Wednesday and Thursday would see the eatern North Island and eastern South Island be the places to be with temperatures "well into the 30s" for several days.

"More heat is coming next week, for sure."

As the warm weather is coming from Australia, he describes the temperatrues as "more heat opposed to humidity".

-RNZ.