Weather: First big winter week about to hit New Zealand

New Zealand is being shaken by thunderstorms and gales on Tuesday as the weather gives us a taste of winter.

A succession of active cold fronts is moving over the country, bringing heavy rain, strong winds and snow.

"This week appears to be the busiest weather week of the year so far with multiple storms and large or deep lows in the Southern Ocean affecting New Zealand with severe weather off and on," Weather Watch warns.

"There are two cold snaps, the first this Wednesday then the second on Friday or the weekend. Both events are surrounded by plenty of windy weather, heavy rain and snow."

Appearing on The AM Show on Tuesday, NIWA meteorologist Chris Brandolino said it's the start of a week of bad weather.

"This will be the first kind of big winter week," he says.

"We're going to find strong winds across the South Island - I think Wellington tonight after eight or nine o'clock... a lot of wind and rain coming after eight o'clock tonight in the Wellington area. Christchurch, strong winds, could be severe gales."

But Mr Brandolino warns this is just the beginning as we get further away from summer. The coldest weather isn't going to come until next week, he says.