Polar blast to blow skifield gates open

Mt Ruapehu is expected to receive large amounts of fresh snow around the middle of this week. Photo / Alex Roberston

A bitterly cold southerly from the Antarctic will sweep up the country this week, bringing snow to all skifields and single-digit temperatures to Auckland.

After an unsettled weekend of weather in which heavy downpours hit Tauranga and large hailstones fell in Helensville, temperatures are expected to drop further on Wednesday in the North Island.

The warmest temperature across New Zealand yesterday was 13C in Cape Reinga, while motorists on the Desert Road were forced to slow down due to flurries of snow.

By midweek, Auckland will be as cold as 7C in the morning, and will also face gusty southeasterlies.

Metservice forecaster Heath Gullery said a strong, cold wind from the Southern Ocean will spread over all of New Zealand from tomorrow: "It is pretty much a cold week for most of the country ... and it will stay that way until Friday."

The drop in temperature has allowed Mount Hutt skifield's beginner and intermediate slopes to open today. The Canterbury resort is the first major skifield to open since a warmer-than-usual May and June prevented natural snowfall on both islands.

Other South Island slopes are still mostly bare - Coronet Peak has a 1cm snow base and Remarkables 2cm. Mount Ruapehu's Whakapapa and Turoa skifields had light dustings of snow but its trails were patchy.

Turoa is expected to open on Tuesday.

Mt Ruapehu will benefit most from the cold temperatures this week, as large amounts of moisture are expected to transform into snowfall.

All South Island slopes are expected to have their tussock and rockfields at least partially covered in white by the end of the week.

Weatherwatch forecaster Richard Green said thermostats in Central Otago may struggle to get above 5C tomorrow and Wednesday.

Mr Green said Christchurch would be hit by the polar outbreak tomorrow afternoon and could struggle to climb out of single figures.

A southerly wind is likely to make the quake-hurt city feel close to freezing point.

The cold snap may be short-lived, as a high is expected on Friday.