Niwa releases record-breaking stats for summer’s extreme rain, winds and storm surges

New Zealand may be facing a new normal of floods, droughts, high temperatures and extreme cyclones, according to a new report by the National Institute of Water and Atmospheric Research.

Niwa’s February climate summary said the country experienced one of its worst weather disasters last month.

“Cyclone Gabrielle caused historic extreme rainfall and river flooding, catastrophic wind damage, and substantial storm surges across the North Island,” a spokesperson said.

“Unfortunately, this culminated in widespread destruction and loss of life, with a long and costly recovery ahead.”

A devastating slip at Karekare on Auckland's west coast after weeks of heavy rain and the effects of Cyclone Gabrielle. Photo / Supplied

Climate records across the country were broken this summer.

Parts of the North Island received at least 400 per cent of their normal February rainfall, Niwa recorded.

The Auckland region received more than 5.5 times its normal summer rainfall and 63 per cent of the entire annual normal. Napier had its third wettest month since records began, receiving more than 600 per cent of its normal rainfall - and 45 per cent of its annual normal rainfall.

The highest single-day rainfall was 316mm, recorded at Tūtira in Hawke’s Bay on February 13.

It was the wettest summer on record for several major centres, including Napier, Auckland, Whangārei, Gisborne and Tauranga.

However, other parts of the country sweltered under the hot sun.

New Zealand also had its third-warmest summer on record - 65 locations experienced record or near-record warm minimum temperatures.

The nationwide average temperature in February 2023 was 18.5C - 1.1C above the 1991-2020 February average.

And the South Island saw its fifth-driest summer on record, Niwa said.

Rainfall was below normal levels in parts of the South Island or even well below normal, as was seen in Fiordland. A meteorological drought developed in Otago during February, with many areas recording less than half their normal summer rainfall.

Greymouth, Westport and Arapito experienced their warmest temperatures on record.

Greymouth recorded seven days with a daily maximum temperature above 25˚C. Between 1972 and 2000, Greymouth only had six total February days when the temperature exceeded 25˚C.

The highest temperature was 35.6°C, observed at Middlemarch, in Otago on February 4.

We can confirm that Greymouth, West Coast had its hottest temperature on record (since at least 1947) on Sunday, reaching 30.9˚C 🥵

This was the first time the temperature eclipsed 30˚C in the town.

The previous record was 29.7˚C from February 2010. pic.twitter.com/G4NFgkz2fu

— NIWA Weather (@NiwaWeather) January 8, 2023

The country also experienced a marine heatwave. Summer sea surface temperatures in the west of the South Island were the highest on record since 1982.

In the north and east of the South Island, summer sea surface temperatures were the second-highest on record.

On Thursday, Niwa said La Nina is also finally leaving New Zealand.

The ocean-driven system has been influencing our climate patterns since the start of the decade, contributing to the northeast’s warm, wet and wild summer, while helping push parts of the South Island into meteorological drought.

In its outlook for the next three months, Niwa reported that La Nina would finally fade to “Enso-neutral” conditions this month – meaning there’d be no dominant climate driver shaping our weather until the expected arrival of counterpart El Nino later in 2023.

“For Aotearoa New Zealand, this transition is expected to result in more variable airflow, temperature and rainfall patterns during autumn,” Niwa meteorologist Ben Noll said.

Out to May, rainfall was equally likely to be near or above normal in the east of North Island, and most likely near normal everywhere else.