Thunderstorms, high winds and heavy rain are expected today in many parts of the country, with weather warnings and watches in place.
Thick smoke and dust has drifted across the Tasman from Australian bushfires, darkening our skies further.
The switch from settled, warm weather to rain and, in some parts, high winds and thunderstorms will be felt across the country, MetService forecaster Sonja Farmer said.
"It's going to be wet everywhere."
In Auckland rain arrived around 6am and is due to worsen through the afternoon, likely putting in doubt the Twenty20 cricket series tie-breaker at Eden Park.
The city is under a 12-hour heavy rain watch from 2pm today with the heaviest rain due around 6pm.
Rain has set in this morning in some areas with the Nelson Marlborough region seeing the worst of it. A heavy rain warning is in place for Nelson until midday.
• Weather: Not such a beautiful day for U2 concert at Auckland's Mt Smart
• Cold and rain breaks 'taste of summer' weather
• Weather: Beautiful Day beckons for U2 fans at Mt Smart Stadium
• Weather: Hot temperatures and a fine weekend ahead for many
Heavy rain warnings have been issued across the country, including in the ranges of eastern Bay of Plenty, Gisborne, Nelson, Westland, Buller and Fiordland. Strong wind watches have been issued across both islands, including for parts of Bay of Plenty, Gisborne, Hawke's Bay, Taranaki, Whanganui, Nelson and Marlborough.
Smoke and dust from bushfires in Australia is also expected to blanket the North Island today. The hazy skies - a result of the 80 wildfires burning through rural New South Wales and Queensland — were visible in the South Island last night.
Niwa tweeted: "The dust & smoke from the #NSWfires is quite prominent on satellite imagery as gets (sic) transported across the Tasman Sea onto New Zealand's South Island. Some of the dust may cross the North Island on Sunday night."
Sky-watchers also saw stunning sunsets as a result with the dust refracting the light. Christchurch residents were last night sharing their snaps.
"There are 81 fires burning in NSW and the smoke has reached New Zealand. Feels like I've ended up in a Mad Max scene with stormy skies to the east," Twitter user Dale Wowk wrote, along with a video of his surrounds. The short clip pans around to show the sky turning an ominous rusty red.