NZ weather forecast: Get the warm coats ready, temperatures set to plunge as MetService says 'golden weather's gone'

Whether you embraced or reviled New Zealand's hottest summer on record, it is now officially the "beginning of the end" for abnormally high temperatures in 2018, say meteorologists.

The autumnal swing towards cooler conditions is already taking place across the country says MetService meteorologist Georgina Griffiths - starting with a "short sharp" chill arriving this week.

"I think the golden weather's gone. The abnormal heat we saw, we had a record warm January, we had a really hot run before Christmas, we had a humid and warm February - that’s definitely gone," Griffiths says.

"The marine heat wave which is part of the driver has diminished, and we should start to see stock standard autumnal changes, short sharp changes."

TVNZ weather presenter Dan Corbett with the latest update. Source: 1 NEWS

And the first of these dips will arrive this Thursday in a "pretty intense change for New Zealand, even for autumn".

Much of the South Island will drop from the low 20 degrees today to low teen temperatures by Thursday.

Christchurch is set for a high of 26 degrees today down to a high of 13 by Thursday.

Wellington is set to dip from 22 today down to 15 by Friday.

However, further up the county the changes will be less marked, with Auckland only going from 24 degrees today to 21 degrees by Friday.

There is even snow forecast for some snow fields on the South Island this week.

"Given we've had five months of warmth it's going to be a bit of a shock to the system, the first decent cold change of the year," Griffiths says.

However, the chill won't be totally long standing, with warmer spells still expected into April.

"We will start to see some warmer spells, I don't think it's over for the whole year, but we are starting to see the decline," Griffiths says.

"It is the time of year when temperatures start to decrease, the autumnal dip."

And while there is no forecast yet for the entire winter, over the next six weeks the temperature is expected to be fairly erratic.

"All I'd say is my messaging for the coming four to six weeks is that we're going to see more changeable temperatures," Griffiths says.

"We start sliding down hill on temperatures and changeability, the mobile weather features, as we move towards mid autumn and into winter.

"The abnormal heat is gone and we would expect temperatures to look quite muted or closer to the average for the first time in quite some time."

Aerial panoramic view of Wellington Cityscape during Sunset - Twilight under beautiful summer cloudscape. Wellington, North Island, New Zealand, Oceania
Wellington is set to dip from 22 degrees today down to 15 by Friday. Source: 1 NEWS