New Zealand’s main weather agency says a strong El Niño is taking shape in the Pacific and it is likely to steer the country’s weather for months to come, with drier conditions on the cards for much of the north and east and a wetter, windier run for the lower South Island.
Earth Sciences New Zealand, the agency that includes the forecasters formerly known as NIWA, says the chance of El Niño conditions forming over winter has climbed sharply. In its seasonal climate outlook for June to August 2026 it puts the odds of El Niño emerging at 95 percent, up from around 65 percent only a month earlier. Forecasters say there is a better than 60 percent chance the event will be classed as strong by spring, and they have not ruled out it becoming one of the bigger events on record.
El Niño is one half of a natural climate cycle in the tropical Pacific Ocean. It is not the same thing as long term, human driven warming, although the two can stack on top of each other. During an El Niño, sea surface temperatures in the central and eastern Pacific run warmer than usual, the pattern of winds and rainfall shifts, and weather changes ripple out across the globe, including to New Zealand.
What makes this forecast notable is the speed of the turnaround. The country has spent recent seasons under the opposite phase, La Niña, which tends to nudge weather in the other direction. Earth Sciences New Zealand and MetService meteorologist Jon Tunster said in the agency’s forecast notes that the switch is happening quickly. “La Niña has only just ended, but there are indications that we’ll see a rapid flip to El Niño,” he said.
For New Zealand, a classic El Niño winter tends to lock in a pattern where high pressure sits over Australia and the wind over the country swings more often from the south west. That funnels rain onto the western and southern flanks of the South Island while leaving the north and east comparatively dry. The latest outlook follows that script. Rainfall is most likely to land below normal across Northland, Auckland, Waikato and the Bay of Plenty, with a 50 percent chance of a drier than usual three months, and the same odds apply to Gisborne, Hawke’s Bay and the Wairarapa. Coastal Canterbury and East Otago are also leaning dry.
The wetter side of the ledger sits over the West Coast and the Southern Alps, where rainfall has a 40 percent chance of running above normal. Southland and parts of Otago are also expected to pick up more rain than the rest of the country as those south westerly winds pile moisture onto the ranges.
A cold winter is not the headline here, despite the southerly leanings. Tunster said a nationwide deep freeze looks unlikely. “It appears unlikely that a nationwide colder than usual winter will occur,” he said, while flagging that short, sharp cold snaps are still on the table, lasting a few days at a time and longer in the inland South Island. There is a chance one month could come in colder than average inside an otherwise close to normal season.
The bigger concern sits further down the track. When rain stays away from regions that normally rely on a wet winter to recharge soils and rivers, the shortfall can quietly build into a problem by the time spring arrives and demand for water climbs. “Dryness could become an issue as spring approaches, for areas that see a reduction in their normal winter rainfall,” Tunster said. The outlook already shows soil moisture and river flows leaning below normal across the upper North Island, the east of both islands and parts of the centre.
That matters most for farmers and growers in the east, who watched dry spells bite in past El Niño years, and for the councils and power companies that keep an eye on river levels and hydro lakes. Earlier strong El Niño events, including the one in 2015 and 2016, brought drought worries to eastern and northern districts while feeding the western South Island, so the regional split in this forecast will look familiar to anyone who farms or tramps in those areas.
Forecasters are careful to stress that a seasonal outlook deals in odds rather than certainties. It points to which way the dice are loaded over a whole season and across a region, not what any single day or town will get. Even so, Tunster said the strength of the developing event raises the chances that the country feels it one way or another. “Given the projected strength of this event, it will be very surprising if New Zealand doesn’t feel some impacts,” he said, adding that “surprises are always possible.”
The event is still building. Earth Sciences New Zealand expects El Niño to keep strengthening through the rest of the year, with peak conditions most likely during the southern summer of 2026 and 2027. That timing means the pattern setting up now is the same one that will shape the growing season, the fire season and the holiday weather many New Zealanders plan around. For now the advice from forecasters is simple enough, which is to watch the updates as the picture sharpens, and for dry leaning regions to keep one eye on water through the colder months rather than waiting for spring to find out where things stand.
What are you seeing where you live, and are you bracing for a drier run or a wetter one this winter? Tell us in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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