Above average temperatures likely in much of Aotearoa this summer – Niwa

It is looking to be a warm summer for much of the country, with a dry spell possible for the holiday period.

Niwa said above average temperatures were likely for most of the motu from mid-December through to early January.

NZ summer climate outlook ️

Favoured to be warmer than average in most regions

️ Periods of wet weather with tropical humidity

️ Dryness/drought risk highest in the south-west of both islands, particularly South Island

Marine heatwave & La Niña = climate drivers pic.twitter.com/kp2veEMZpi

— NIWA Weather (@NiwaWeather) November 29, 2022

Subtropical northeast winds could result in more frequent hot days inland and in the west, while the east could see fewer scorchers.

The drought risk is elevated for the south of the South Island, while a continuing marine heatwave could fuel heavy rainfall events.

The country’s risk of ex-tropical cyclones remains at normal to elevated levels.

Climate scientist Dr Jim Salinger said this year could end up being one of the warmest on record.

There had been a run of record temperatures in recent years, he said.

“If we look at the last five years where clearly it’s the warmest period we’ve had since records [began] dating back to 1870.”

The La Niña weather pattern and climate change were driving the hot weather, Salinger said.

La Niña continued during November and a marine heatwave in New Zealand’s coastal waters led sea surface temperatures to be 1.1C to 1.7C above average, Niwa said.

This would influence the summer climate, it said.

A moderate () to locally strong () marine heatwave developed in Aotearoa New Zealand’s coastal waters during November

This is expected to influence the summer climate, with warmer temperatures & greater moisture availability overall. pic.twitter.com/NiUbNRDF6h

— NIWA Weather (@NiwaWeather) November 28, 2022

Niwa meteorologist Chris Brandolino said it was the third consecutive summer in which La Niña was the main climate driver.

“The climate driver is basically who is in control, who is at the steering wheel of Mother Nature’s car and La Niña is at the steering wheel.”

As a result there would be fewer westerlies which would affect Canterbury, Hawke’s Bay and Gisborne in particular. They would experience more easterlies so temperatures would not reach the peaks caused by nor’westers.

There was also a higher chance of “significant rainfall” events for the upper and eastern parts of the North Island and to a lesser extent the east coast of the South Island.

While summer has officially started today, it would feel more like early or mid-spring but the cool start over the next few days would not define the summer season, he said.