Temperatures in some parts of the country are set to plummet, which after a week of scorching heat will come as a relief to many.
But it'll only be a temporary reprieve, WeatherWatch said on Wednesday, with the weekend shaping up to be another dry, hot one.
"There's a significant cooler change moving up the South Island today and tomorrow as another high pressure system rolls in from south of Australia," the forecaster said on Wednesday morning.
"As a new high arrives they often bring a southerly flow to begin with."
By Thursday, Invercargill's high will drop to a mild 13C - a "whopping 19C" fall from Monday.
"Daytime highs in coastal Southland look to remain lower for a week ahead, although should make it back into the low 20s," said WeatherWatch.
Dunedin is also expected to peak at 13C on Thursday, and Christchurch 15C.
"The further north you go the less impact the cooler change has - but it still has some impact," said WeatherWatch, predicting 21C in Manawatu - down 10C.
North Island temperatures will bottom out on Friday before rising again over the weekend, according to the forecaster's modelling.
Forecasting by NIWA Weather backs this up, with Auckland's high dropping from 25C on Wednesday to 22C on Friday, before rising back to 26C early next week. Rotorua's 28C on Wednesday will be followed by 24C on Thursday and 22C on Friday, followed by a return to the mid-20s by Monday.
Hamilton's high is predicted to rise from 27C on Wednesday to 29C on Thursday, according to NIWA, before plummeting to 22C on Friday before - like the rest of the island - heading back up next week.
But there's trouble brewing on the horizon, with a potential tropical storm brewing just north of the country.
"The modelling has become more consistent of a large low pressure zone directly north of us, around Vanuatu - Fiji area," WeatherWatch said.
"The future course for this low wants to take it directly into New Zealand - but with New Zealand dealing with a very powerful belt of high pressure at the moment there is still a lot to work out about future tracking potential."
