Get set for rain: Weather set to take a turn for the worse
Rain and snow are forecast as weather conditions start deteriorating from Wednesday - the shortest day of the year.
Snow is forecast for higher parts of the South Island and strong, gusty winds and rain for the North Island at the end of the week, thanks to a potent subtropical storm moving through the Pacific.
But before that happens, MetService said conditions were looking good for Tuesday night's rugby match between the Lions and Chiefs in Hamilton.
The forecast is mostly fine for New Zealand on Tuesday, though Northland is expected to have some showers, and some are also possible on Coromandel Peninsula. A few isolated showers are possible from Gisborne to Wairarapa, with a few showers also in the forecast for northern Westland and Fiordland.
For Wednesday, MetService is forecasting possible heavy rainfall and gale northeasterlies in Northland and Auckland, rain is expected on the Coromandel Peninsula, with drizzle developing in Bay of Plenty, Taranaki, Rotorua and Gisborne.
Rain is expected to spread everywhere on Thursday, with heavy falls possible in Northland, Auckland, Coromandel Peninsula, Bay of Plenty, Rotorua, Gisborne and Taranaki.
MetService is predicting snow to 500 metres in the Canterbury high country on Thursday, while Niwa said snow was expected to accumulate above 300m across much of Otago, with the most snow likely across interior Canterbury.
Niwa said the shortest day on Wednesday would have nine hours and 37 minutes of daylight in Auckland, nine hours 11 minutes in Wellington, and eight hours 35 minutes in Invercargill.
It said the bad weather in the second half of the week was the result of the subtropical storm diving south.
Pinhole area of low pressure swirling to the north of New Zealand. Rain+humidity+snow+wind among the late week impacts 🌧🌨🌬 pic.twitter.com/43YTWEcdtx— NIWA Weather (@NiwaWeather) June 19, 2017
"Driven by an atmospheric river of moisture originating near Vanuatu, rain may become heavy across Northland on Wednesday night, before moving south into Auckland early on Thursday, Niwa said.
"Accompanying the rain will be strong, gusty northeast winds that will linger into Thursday for much of the top of the North Island."
Some of the storm's heaviest rain was expected to fall from the eastern Coromandel Peninsula, through Bay of Plenty, and to East Cape from Thursday through Friday, Niwa said. Those areas may be the most prone to localised flooding and slips as total rainfall may exceed 150mm in spots.
On Tuesday, rugby fans in Hamilton can expect a sunny day, after morning fog, with a 16C high.
Elsewhere Tuesday started chilly in parts of the South Island with Timaru getting down around -2C, Alexandria around -3C, and Queenstown around -2C.
In Auckland cloud is expected to increase on Tuesday afternoon, with a strengthening easterly and a 17C high. Wellington is expecting a fine day with developing northerlies and 14C. Christchurch is forecast to have a fine day with northeasterly breezes and 11C.