Severe gales, heavy snow and heavy rain are set to batter the country on Tuesday and Wednesday as a cold southerly sees temperatures drop.
While temperatures remain above average on Tuesday, they are set to plummet for most of the country on Wednesday.
In the upper North Island 100km/h winds are predicted and Weather Watch warns power cuts and falling trees are possible from Auckland to Cape Reinga.
NIWA meteorologist Chris Brandolino told The AM Show on Tuesday it's going to be a cold week.
"In Auckland the wind is going to be quite bad tomorrow [Wednesday], the air temperature will struggle to reach 12 degrees, there will be rain, hail, a bit of thunder thrown in perhaps," Brandolino warned.
But he said there is good news for Wellington, Hawke's Bay and the South Island's West Coast which have the best weather for Tuesday.
"Hawke's Bay looks actually pretty good. They are an island in terms of the weather with 16 degrees today."
But Brandolino warned it's not going to last with Wednesday predicted to bring bad weather for most of the country.
The South Island isn't unscathed with snow down to a few hundred metres overnight and downpours in Southland and Otago. Weather Watch says the temperature is expected to drop by a couple of degrees on Wednesday as well.