Antarctica's September Weather Driving Current Hot Windy Conditions

Thursday, 23 October 2025, 5:08 pm
Article: RNZ

Alexa Cook, Hawke's Bay and Tai Rāwhiti reporter

Antarctica's warm weather in September is driving the gale force winds and hot temperatures being felt across New Zealand this week.

Temperatures could reach nearly 30 degrees in Hawke's Bay on Thursday and the region is under a strong wind watch as fire crews work to try and contain a huge bush fire near Porangahau.

Earth Sciences Meteorologist Chris Brandolino told RNZ the weather patterns being experienced nationwide can all be traced back to what was happening in Antarctica in September, when the top of the atmosphere got really warm, really quickly.

"Because of that, there were flow on effects... that polar vortex weakened and became wobbly and oblong shaped.

"That low pressure that is frequently over the continent of Antarctica got displaced into the Southern Ocean... that has really accentuated the pressure gradient," he said.

Hastings and Havelock North are expected to hit 29 degrees today, which is one of the factors that resulted in a total fire ban for the Hawke's Bay District until the October 27th.

Brandolino is helping Fire and Emergency with their fire risk forecasting, and told RNZ the soaring temperatures and high winds can create problematic conditions.

"Conditions are dry, we haven't had much rain in the Eastern part of the North Island so that's helping to set things up with high end fire risk," he said.

Three fires are burning in Porangahau, one is 250 hectares in size and hasn't been contained yet due to high winds grounding helicopters.

Brandolino said parts of Napier and Hastings had already reached more than 20 degrees by 8am this morning, and will keep climbing by nearly 10 degrees throughout the day.

It'd be the second time for temperatures to reach those heights this month.

"It is certainly unusual but it is not unheard of," he said.

Brandolino explained that we've seen low pressure favouring the southern ocean since September, and high pressure in the north eastern parts of New Zealand. Those two factors have created a steep pressure gradient, resulting in brisk winds.

"Spring usually features these changeable conditions that wind thrives off, but this has been next level," he said.

More 'potent' high winds and hot temperatures on the cards

Keep the trampoline tied down and the sunscreen handy as the hot windy weather is far from over, with more on its way at the end of the long weekend.

"Another warm surge of air comes down, probably Labour Day and the following day... that could be potent as well.

"It'll bring with it another surge of warmth, another surge of wind - and that's something we need to be mindful of," said Brandolino.

He's warning kiwis that we'll see very changeable conditions over the next few weeks.

"We'll get days where it feels like summer, and then couple days later it kinda feels like early Spring again.

"Don't get too comfortable or complacent with the weather because it'll likely be highly variable," he said.

The chance for some more rainfall on dry regions will increase later in November.

"We'll see a change in wind direction, and that could mean a change in rainfall patterns. Northern and Eastern parts of the North Island could have a wet lean," said Brandolino.

'Very disappointing' - FENZ on people lighting fires

Fire and Emergency is disappointed in people lighting fires overnight and is warning that in the current conditions it will be very difficult to control any fires that get out of control.

There's a heightened fire risk on the East Coast of both islands due to high winds, warm temperatures and low humidity.

A total fire and fireworks ban is in place for Canterbury, Marlborough, Wellington and Hawke's Bay but Ken Cooper from Fire and Emergency said people weren't listening.

"We have been called out yesterday and overnight to people lighting drum fires and having back yard burns and burn offs across the country and in Hawke's Bay.

"That's very disappointing to us as we've been very clear with our messaging that this is a very significant weather event," he said.

With a four day weekend beginning on Friday in Hawke's Bay, he said there was concern about people's attitudes.

"We're really asking the Hawke's Bay community to be extra vigilant. There is a ban on all open air fires including fireworks.

"Even the slightest spark in windy conditions can cause fire to spread quickly. This puts people at risk and also endangers our firefighters," Cooper said.

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