The weekend is expected to bring sunshine, with highs of up to 13C.
Frosts are likely from Northland to Manawatu tonight, and heavy showers that were last night lashing Kapiti, Wairarapa and Wellington are expected to hit coastal Wairarapa today.
Roading authorities were last night preparing for severe frosts expected in inland Otago.
Grit was being spread on some road to reduce the danger of packed snow turning to ice, and and contractors will be out again today.
In Dunedin, Sergeant Ed Baker said "dozens and dozens" of crashes happened on the city's snow-strewn streets, most involving a slow speed slide in to the gutter or a parked car.
Police also dealt with many reports of drivers taking unnecessary risks by taking advantage of the slippery conditions to do burnout and donuts.
The city was isolated for a time yesterday when snow closed the the northern and southern motorways closed.
The road south was re-opened by 8.30, followed six hours later by the Northern Motorway.
Ice on the runway at Dunedin International Airport resulted in 10 inward and outward flights being cancelled yesterday morning, and in Dunedin, electricity demand hit record levels.