A satellite image showing Tropical Cyclone Tam on its way towards New Zealand in April 2025.
A satellite image showing Tropical Cyclone Tam on its way towards New Zealand in April 2025.
Australians are bracing for a volatile cyclone season driven by record-breaking ocean temperatures – but could that same threat be heading across the ditch to New Zealand?
According to the Tropical Cyclone Outlook released last month, Earth Sciences New Zealand (ESNZ) said parts of New Zealand are at anormal and higher-than-normal risk of cyclones for the 2025-26 season.
ESNZ is predicting five to nine cyclones could hit the Southwest Pacific region during the season, with nine traditionally being the long-term average.
Over the ditch, Australian experts said sea surface temperatures in northern Australia are sitting well above normal, news.com.au reported.
Weatherzone meteorologist Ben Domensino told news.com.au that tropical cyclones need a sea surface temperature recording at or above 26.5C to form.
“Once over this threshold, the rate at which tropical cyclones can intensify generally increases with higher ocean temperatures,” Domensino said.
In some northern Australian regions, ocean temperatures have peaked at 31C, which is in the top 10% of historical records for this time of year.
ESNZ’s principal scientist Chris Brandolino says New Zealand typically experiences about one ex-tropical cyclone a year.
ESNZ’s principal scientist Chris Brandolino told the Herald the outlook for New Zealand was assembled with the warm ocean surface temperatures in mind.
“In a nutshell, ocean temperatures, while very important, are not the only thing that influence how tropical cyclones of the season may go, if it’s a busy season or a quiet season,” he said.
Brandolino said the area they issue an outlook for is different from the area that Australia does.
“There is a bit of overlap, but generally speaking it’s a different area than what Australia monitors.
“Our outlook covers the Southwest Pacific, which basically goes from just south of Papua New Guinea, over what’s called the Gulf of Carpentaria ... and that goes all the way east to French Polynesia.
“It is a big chunk of real estate,” he said.
Brandolino said, on average, New Zealand experiences about one ex-tropical cyclone a year.
New Zealand, and specifically northern New Zealand, are in the one to two ex-tropical cyclone range this season.
“This year, that risk is considered normal to elevated,” he said.
Cyclone risk for Southwest Pacific Islands
A graphic showing the Earth Sciences New Zealand/MetService assessment of the risk of cyclones hitting the Southwest Pacific basin from November 2025 to April 2026. Photo / ESNZ, MetService
There are significant differences expected between the western and eastern halves of the basin from November to April.
“Normal to reduced risk is anticipated for the central part of the basin, and reduced risk is expected for the eastern part of the basin,” ESNZ said.
A graphic showing the Earth Sciences New Zealand/MetService assessment of the number of cyclones expected to hit the Southwest Pacific basin from November 2025 to April 2026. Photo / ESNZ, MetService
Northern New Zealand, Tonga, Wallis and Futuna, and the Solomon Islands are likely to see one to two cyclones during the season.
Fiji is at risk of seeing two to three, while New Caledonia and Vanuatu are at risk of seeing three to four.
“Between two and four severe tropical cyclones reaching category 3 or higher may occur anywhere across the region, so all communities should remain prepared,” ESNZ said.
ESNZ, MetService, the University of Newcastle and meteorological services across the Pacific Islands created the report, with ESNZ thanking the other organisations for their contributions.
ESNZ was known as Niwa, the National Institute of Water and Atmospheric Research, until July this year when it was merged with GNS Science to create the new organisation.
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