Sub-zero temperatures are forecast to hit most of the country

Sub-zero temperatures are forecast to hit most of the country on Sunday and into the start of the new week.

It's perfect weather conditions to bundle on the thermal underwear, with the official start of winter only six days away.

Even with plenty of sunshine, Auckland is expected to hit highs of just 13C through to Tuesday.

Southland and Coastal Otago will get highs of just 8C on Sunday and Monday, according to WeatherWatch analyst Phil Duncan.

Highs in Queenstown will be between 2 and 3C with overnight lows of -6C, with Wellington tipping the mercury at just 10C at its warmest point.

"We have another cold front moving up over the South Island and with that we'll be getting rain, possibly heavy for places like Southland, Fiordland, Clutha and scattered showers for central Otago and Dunedin," said MetService meteorologist April Clark.

Overnight, freezing temperatures are expected for parts of the South Island, such as Alexandra.

Another low will creep eastward over the country on Sunday, bringing strong winds to the southern and eastern coasts and possible severe southerly gales from Banks Peninsula to Gisborne.

Temperatures will drop again as skies clear overnight.

On Monday, there's a small chance of heavy snowfall about north Canterbury and the Kaikoura Ranges above 400m.

Then mid-week, a ridge of high pressure is expected to build over the South Island as the southerly flow over the North Island eases.

MetService has issued snow warnings for a number of roads.

Overnight tonight on the Crown Range Road, light snow is likely down to 900 metres.

On Milford Road, occasional snow showers are possible down to 800 metres overnight tonight.

Tomorrow night, snow is forecast on the Desert Road down to 700 metres.

And from later in the afternoon tomorrow overnight until Monday morning, Lewis Pass will experience snow down to 500 metres, and Porters Pass down to 600 metres.