Wednesday morning has been the coldest of the week so far for the North Island, and some temperatures in the South Island dropped below zero overnight.
In St Arnaud, at Nelson Lakes, the overnight low was -6.5 degrees, in Twizel was -5.4 and Mount Cook was -5.
MetService meteorologist Clare O'Connor said Queenstown was the coldest main centre, reaching -1 overnight.
Christchurch dropped just below zero, to -0.6.
It follows a day of snow fall and road disruption on Tuesday.