NZ weather: Another winter cold snap arrives, sub-zero wind expected for days in Dunedin

The South Island has been hit by another winter cold snap, whipping up icy winds not expected to relent until the weekend.

A cold front has moved through the south quickly propelling temperatures downwards, including in Dunedin where the warmest it will get in the next four days is 6C, according to WeatherWatch.

The wind chill in the southern city sat at -1C on Wednesday morning and is expected to only reach 0C by midday. Windchill there will "hover between 0C and -3C continuously until almost noon on Sunday when it finally climbs up to 1C".

"Across Southland windchill of -2C and -3C is fairly consistent over the coming days but may warm up a little to 3C at times due to wind flows shifting around," WeatherWatch says. 

"Christchurch isn't quite so cold but still drops down to a windchill of -3C at times overnight, but by day should be closer to around 5 to 7C, considerably milder than Dunedin."

Snow flurries are forecast across the lower South Island, down to 300m in Otago and Southland, 400m in south Canterbury and 700m in north Canterbury on Wednesday.

Weatherwatch says there could be snow flurries down to 100m in Southland and Otago "depending on various squally showers" but it's "far less likely to settle" and would occur overnight. 

Snow totals over the remainder of Wednesday and Thursday aren’t especially high, with perhaps only a further 15cm likely on the mountain summits now that the main front has gone through.

While this week's weather event "isn't as significant" as the polar blast that froze the country last week, for "Southland, Otago, Canterbury high country and the North Island’s Central Plateau the cold, wintry, airflow may linger longer" - potentially until the weekend. 

"Snow flurries will likely impact some highways and windchill will be very tough for newborn lambs, along with showers/damp conditions - especially in Southland and coastal Otago," says WeatherWatch.

For the North Island, the coldest spots will be Waiouru, Ohakune and National Park/Central Plateau. 

"The windchill here will be mostly below zero from Thursday to Saturday with air temperatures climbing to a maximum of about 4 or 5C from [Thursday]. Snow flurries are possible in this region and on the Desert Rd, although accumulation doesn’t look too extreme."