Black ice warning for tonight

Severe frosts expected throughout New Zealand tonight could see the country's road covered in black ice. File photo / NZ Herald

Weather analysts are warning that severe frosts throughout New Zealand could see the country's road covered in black ice.

Severe frosts expected in many areas of New Zealand tonight as skies continue to clear following this week's Antarctic blast, according to weatherwatch.co.nz.

Head weather analyst Philip Duncan said it will be extremely cold in Southland, Otago and Central Plateau with severe frosts expected.

"With little wind and cloud any warmth from the day disappears at night and the coldest air sinks down into the valleys. Some areas overnight will be dropping below -10 tonight in the lower and central South Island."

He added that frosty conditions will stretch from Southland to Northland with severe frosts in the south and light to heavy frosts in the north.

"With so much snow melt and wet roads there is an extremely high risk of black ice on Friday morning - and that risk will become more and more widespread over the next few days as this high slowly pushes in and the showers in the east clear".

WeatherWatch.co.nz says even areas with cloud and nearby showers may have frosts - such as Canterbury.

Frequent showers and brisk winds on the North Island's east coast from Wellington to Gisborne reduce the risk of frost in these areas.

Heavy to severe frosts are also expected from inland Taranaki to King Country and Waikato.

- HERALD ONLINE