MetService Weather 17th September 2025. Video / MetService
Thunderstorms, strong northwesterly winds and heavy rain are lashing the South Island, with the lower North Island next in the firing line later today.
Gusts in exposed locations like the Canterbury high country could reach 130km/h, which poses a “dangerous” risk to motorists.
MetService meteorologist John Law toldthe Herald, the wild weather will move up the west of the South Island before reaching the lower North Island by the evening.
“It’s a bit of a resurgence of that springtime weather of unsettledness that comes through,” Law said.
“It’s a real change, a real swing back to strong northwesterly winds, heavy rainfall, thunderstorms. There’s plenty happening.”
He said the South Island will bear the brunt today, with the heaviest rainfall with “intense bursts” expected on the western side of the southern Alps.
Severe watches and warnings
Most of the South Island is covered by severe weather watches and warnings over the next few days as the weather begins to shift.
The ranges of Westland and the headwaters of the Canterbury lakes and rivers south of Lake Marion are under an orange heavy rain warning until 10pm tonight.
The headwaters of the Otago lakes and rivers, and Fiordland north of Doubtful Sound, are under the same warning until late this afternoon.
Most of the South Island is covered by severe weather watches and warnings. Image / MetService
Wellington and the Canterbury high country are under an orange strong wind warning, with concerns for damage to trees, powerlines, and unsecured structures possible.
A number of other regions are also under strong wind and heavy rain watches today and tomorrow.
A heavy swell warning is in place for Kapiti-Porirua Coast – Otaki to Cape Terawhiti tomorrow.
Even once the main band of rain has passed, showers will linger before clearing by the end of Friday.
Temperatures heating up
MetService meteorologist Mmathapelo Makgabutlane said that last week parts of Hawke’s Bay struggled to reach double-digit temperatures, but this week highs in the 20s will be common across eastern areas.
Auckland is set to reach a high of 18C, but Wellington is forecast to drop to 15C after reaching 20C yesterday.
“We’re looking at highs in places like Christchurch of around 22C,” Law said.
“That’s a little bit warmer than normal for the time of year.”
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