1 Dec 2019

More heatwaves on the way for summer - Niwa

8:13 am on 1 December 2019

New Zealanders can expect more above average temperatures for summer across the country, according to Niwa's outlook.

Wellington summer 2018
Oriental Parade

New Zealanders soaking up the sun in Wellington last year. Photo: RNZ / Richard Tindiller

It kicks off with a windy start, as December is forecast to be blustery, particularly for the Western parts of the South Island which could get stormy.

Niwa meteorologist Ben Noll said while everyone would get rain, it would be spread across the season.

Except for the West Coast where rain will hit early in the season, which could lead to flooding in parts.

But overall, normal rainfall levels are predicted.

Mr Noll said there would be plenty of sunshine to go around.

"I'd say early summer weather will be driest and best in the North Island but the late summer could turn drier in the South Island,"

Holiday-makers could also rejoice with heatwaves set to become a regular occurrence around the country through November and December, he said.

"Heatwaves will be probably coming through semi-regularly as we go through the month of December.

"Certainly some warm conditions if you're living in the east of both islands.

"We've seen record or near-record temperatures, dozens of them as we went through November ... we could be dealing with more of that as we go through the rest of the summer season."

Warm oceans

But it's marine heatwaves that are pushing up the temperatures.

He said the hot weather was due to the warming ocean around New Zealand.

"Our ocean temperatures are warming up, and the last couple of years we've had marine heatwaves in our coastal waters.

"We are watching very closely here late November, early December ... it looks like they're warming up once again and that can be a driver of warmer than average air temperatures as we go through the summer season," Mr Noll said.

Climate change was definitely part of the conversation, he said.

"We live in a warming world. So these temperature extremes, they become more likely, the warmer our temperatures get.

"So those 30 degree days or 35 degree days certainly will be with us as we go through the summer season and they're made more likely when we have warm oceans that are surrounding New Zealand."

Rural sector

Farmers across the eastern North Island who are suffering from the dry spells will have to wait a little longer.

He said the Hawke's Bay, Wairarapa through to the Bay of Plenty, Waikato, Auckland and Northland were already very dry.

"It looks like December is going to be quite dry in the eastern North Island so those places that already are dry can experience drier conditions yet as we go through December."

But Auckland, Northland and Waikato might get some relief early.

"There could be some rainfall events as we go through the first week of the summer season, that would be beneficial rainfall."

Water restrictions

Napier has started water restrictions, which is a little early in the season - but more places could soon follow suit.

"New Zealand, especially some parts of the North Island, are running rainfall deficit as compared to normal year to date. So 2019 started off in a very dry fashion for large parts of the North Island," Mr Noll said.

"Places certainly [where there have] been running rainfall deficits will need to keep a close eye on their water usage as we go through December, because some areas expect that dryness to continue."

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