Cold air from around Antarctica was mixing into the airflow spreading up the South Island on Saturday evening while warmer than average air from the sub-tropics impacts the upper South Island at the same time. The warmer than average nor’west flow is gradually moving off the country as the deep storm in the Southern Ocean churns by.

Earlier Saturday evening Kaikoura was on 21 degrees while Suva and Nadi in Fiji were only two degrees warmer on 23.

As of 10pm Saturday Invercargill was around 3 degrees while parts of northern Canterbury were still on 17 degrees.

The colder change will gradually spread northwards as the more polar air mixes with the south west change moving across the country.

Gale force winds in Wellington are gusting to 100km/h on Saturday night – with winds increasing in many places across Sunday.

Here’s the 10pm update:

Polar air and sub-tropical air are mixing into the big westerly quarter flow across the country this weekend, making for a real variety in temperatures. (Saturday evening map).

– Temperature map via Wunderground & community stations

– WeatherWatch.co.nz