It might feel like four seasons in one day for Auckland, with bursts of heavy rain and drier breaks in between, amid strong winds and even lightning for the first day of the week.
Meanwhile the South Island is clearly in winter mode, with heavy snow in the ranges and cold, sleety rain in the lowlands.
And while the rain might subside, by mid-week the whole country will feel firmly in winter, with "blizzard" conditions forecast on Wednesday, with particularly cold and windy weather expected.
MetService meteorologist Mmathapelo Makgabutlane said the severe Auckland weather is thanks to several troughs moving across the country, and later a low pressure system crossing the upper North Island, bringing spells of wet weather.
Aucklanders can expect frequent showers - some heavy and possibly thundery - and westerly winds from this afternoon. Those winds will be strong in exposed places, locals are warned.
Satellite image this morning showing a large swathe of cloud lying to the east of New Zealand that brought heavy rains and strongs winds overnight. Photo / JMA
Water usage recently has also been well below the targeted savings level of 409 million litres a day (MLD), with Aucklanders on Sunday consuming just 378 million litres, bringing the seven-day average to 398MLD.
Emergency services had a busy night, with up to 50 weather-related call-outs around Auckland, Northland and Waikato.
Severe weather overnight wreaked havoc as a downpour of heavy rain and wild winds ripped through Auckland, Northland and Waikato with up to 50 weather-related call-outs.
A Coastguard spokesman said around the region overnight, winds picked up to 60 to 65 knots - around 120km/h. There were no call-outs overnight, he said.
Makgabutlane said as of midday most of the severe weather in the upper North Island had passed, with just some heavy showers this afternoon and potential thunderstorms.
The focus now was on the lower South Island, with low developing east of Otago, directing a southerly flow and rain onto Southland and eastern Otago.
Heavy rain watches remain in force for Southland and eastern Otago.
The low should move away to the east on Tuesday morning and the rain should ease.
Meanwhile, a trough is forecast to move eastwards across the North Island on Tuesday, and westerlies should become strong in many places.
A strong wind watch is now in force for the Tararua District and Hawke's Bay south of Napier.
Mangatawhiti dam in the Hunua Ranges as of July 2. Photo / Watercare
A broad area of low pressure over the South Island is expected to move east on Tuesday, passing a showery trough and strong westerlies over the North Island.
A cold front follows from the south Tasman Sea, bringing a bitterly cold southerly, which is expected spread over the country during Wednesday and Thursday, bringing snow to low levels about the South Island and to the North Island ranges and central high country.
Wintry showers and southwesterlies ease on Friday.
On Tuesday, strong to gale westerlies spread over the central North Island, with a low risk of severe gales about Taranaki, the central high country, Gisborne, Hawke's Bay and the Tararua District.
During Wednesday and Thursday, there is a low risk of severe gale west to southwesterly winds about Northland, Auckland, and Coromandel Peninsula, with a moderate risk of severe southerly gales about the east coast of the South Island and North Island between Otago Peninsula and Mahia, including Cook Strait.
Cold temperatures are expected, with snow to low levels about eastern and southern parts of the South Island, and about the central plateau of the North Island.
There is a moderate risk snow accumulations will exceed warning amounts above 400 metres about southern Fiordland, Southland, Clutha, Dunedin, southern parts of central Otago and Banks Peninsula.
Blizzard conditions are likely about South Island hills and ranges exposed to the southerly gales, and high level roads are likely to be affected by snow, including the Remutaka and Desert Rds.
