Our rollercoaster winter: settled now, wild later
Sunday, 14 June 2026
Kevin Norquay is a senior writer for The Post and Sunday Star-Times. This is his weekly explainer.
It’s winter, but what kind of winter will it be? All kinds of everything across two distinct phases, says weather forecasting guru Chris Brandolino of Earth Sciences NZ.
Kiwis should prepare for a 'winter of two halves', the principal scientist warns.
It sounds as if North Islanders will have less cause to call on heaters, electric blankets and raincoats initially, South Islanders (especially in the west) will need wet weather gear, and umbrellas will be no match for the winds of late winter and spring.
Settled then turbulent, with the north experiencing a drier than usual winter, and the south and west South Island likely wetter than average.
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Overall, winter begins with deceptively settled weather, then pivots into a rollercoaster, marked by strong wind events, temperature swings, and a lack of rainfall where it is needed most.
The engine is El Niño, a massive climate driver currently forming in the tropical east Pacific Ocean off South America.
For El Niño to take hold the ocean and the atmosphere must sync. The central and eastern tropical Pacific is experiencing sustained, unusual warming. The atmosphere is still arriving.
'El Niño is really on the precipice, on the cusp of formally being developed or being present,' he says, morphing into human romance to explain.
'The analogy I like to give is if there's a wedding, and two people are going to become a couple … at the moment we have the ocean just about to arrive at the altar, it's not quite there, but boy, it's a step away,” he says.
“Still lagging a little bit behind is the atmosphere … it is coming down the aisle, they will become coupled, it’s imminent.”
Once that 'marriage' takes place, the flow-on effects will travel thousands of kilometres altering prevailing weather patterns in late winter and spring.
The shift will be driven by two intensely competing pressure systems: high pressure over the North Island, low pressure intensifying over the Southern Ocean.
Between them is what he calls a steep pressure gradient, the squeeze between low and high pressure systems is the atmospheric equivalent of a steep hill (and sorry central North Island, that’s where you come in).
“Think of it like an elevation gradient, going from the top of a mountain to the bottom of a valley. If the elevation changes really fast, like on a steep hill, that water would flow pretty quickly,” he says.
“High pressure is the mountain. Low pressure to the south is the valley … and that's going to likely facilitate some pretty impressive wind as we move into late winter, and especially spring.”
It won’t be a revolution, more an evolution, with the pattern gradually moving away from largely settled to largely unsettled.
While places like Wellington are notoriously windy by default, the upcoming pressure gradient threatens to bring wind speeds well beyond its seasonal norm, ramping up significantly in August and tearing into a highly turbulent spring.
For most readers winter will be distinctly drier, then more windy - though the West Coast, Fiordland, Southland and parts of Otago near the Southern Alps can add moisture.
Brandolino disavows having knowledge of any use to those who are keen to brush off their skis and snowboards, but he does point out snow requires a perfect marriage of moisture and cold.
Given the North Island is staring down a drier-than-usual winter combined with a warmer start, North Island ski resorts such as those on Mount Ruapehu may face a frustrating season.
But the lower and western South Island - Queenstown and Wanaka - are much closer to the southern low-pressure moisture track. After a warm start late winter promises to be more lucrative.
And while a string of sunny, crisp winter days might sound pleasant to most of us, there’s a sting in the tail, and Brandolino is concerned for the long-term outlook.
Winter is critical as the primary season for 'groundwater recharge' - essentially refilling the subterranean reservoirs before the heat of summer arrives to evaporate them away.
'We need to get the ground kind of like a battery, we need to recharge it with water, recharge it with moisture,” he says.
“Unfortunately, there is a real chance the groundwater recharge may be inadequate for much of the North Island.'
A single dry month is not the problem, it’s the snowball effect of a dry winter rolling straight into a parched spring and summer, supercharged by relentless El Niño winds.
In real-life terms that raises the costly risk of out-of-season wildfires and agricultural drought.
And where’s that going to be a problem?: Wairarapa, the eastern North Island (where it’s already very dry) and northern North Island.
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