Kiwis are being warned to prepare for some chilly weather in the next few days as cold temperatures make their way up the country.
Low pressure south of New Zealand and high pressure south of Australia will team up to bring southwesterly winds during May.
MetService meteorologist Mmathapelo Makgabutlane told Newshub Kiwis can expect the colder temperatures to hit the South Island first.
"Over the coming week across New Zealand, temperatures at the end of the week will look very different to how they look at the start," Makgabutlane explained.
"On Tuesday and into Wednesday, we have a weather system moving upwards, up the country, and behind that is cold air which is what we'll be feeling in those colder temperatures this week."
For the North Island, Makgabutlane said temperatures are decreasing from Thursday into Friday, "mainly into central parts of the island and eastern parts, and then into lower parts of the island too".
Taupo can expect a high of 13C on Thursday, along with Taumaranui. Meanwhile, further south, Wellington can also expect a high of 13C.
In eastern parts of the island, Masterton will drop to a high of 14C on Thursday.
"The coldest morning of the week will be Saturday, where parts of the central North Island, specifically Taumaranui, will plummet to 2C," she said.
"On Saturday morning there will be possible frost outside, and for those in Auckland it will feel pretty chilly waking up to 9C to start the day."
In the South Island, Kiwis are warned to expect those snappy temperatures earlier, from as soon as Wednesday.
"Parts of the Southland and Gore will see a high of 10C on Wednesday, while Invercargill and Dunedin will reach 11C max."
Makgabutlane said Queenstown's high will be 12C on Wednesday.
"It will be quite cold down there," she added. However, she said there "won't be any significant snow in the South Island".
And she has some advice for those wanting to be prepared.
"Keep an eye on the forecast, make sure to have your winter blankets out, and don't underestimate those colder temperatures before heading out the door," she said.
"It's that time of year where those winter blankets are definitely needed."
The warning comes after NIWA forecaster Chris Brandolino spoke with AM on Monday to explain the difference between La Niña and El Niño.
"El Niño and La Niña are basically like a seesaw," he explained.
"When we have El Niño, the water is unusually warm out towards the Galapagos Islands, out towards South America.
"Meanwhile, further to the west, towards Fiji, New Caledonia, north of Australia - the water is unusually cool - and that's El Niño.
Brandolino said La Niña "is the complete opposite".
"We have all this cool water out towards the Galapagos Islands and out towards South America. Then we have unusually warm water out towards Fiji and New Caledonia.
"So, that brings a different weather pattern, or different weather regime across the globe, including Aotearoa New Zealand."
Brandolino said it's expected by springtime, there is a 60 to 70 percent chance that La Niña would have developed.
However, he said when it develops people won't see change automatically.
"It happens over time. These are things that happen over several weeks, several months."
