Heavy frosts expected tonight could lead to treacherous driving conditions in the morning.
Clear skies over inland and sheltered areas across the country will result in sub-zero temperatures, prompting police to urge motorists to drive to the
MetService expects Waiouru to reach -4C and Queenstown and Alexandra to dip to -5C. Wanaka is expected to fall to -3C.
"The skies are really clear and there is a high chance of good frosts tonight," forecaster Mike O'Connor said.
Frosts were likely to hit anywhere that was sheltered from the southwesterly winds, he said.
Central District road policing manager Inspector Dave White said winter provided challenging driving conditions including snow and black ice on roads.
He said there were a number of crashes in the district this morning from black ice, "so I want to remind drivers that they need to be alert and adapt their driving."
Snow and ice yesterday closed a number of highways across the country, but they had all reopened today.
Meanwhile, police were warning drivers they would be on the lookout for speeding vehicles over Queen's Birthday weekend.
For the duration of the Queen's Birthday holiday period, the speed limit tolerance was 4km for all permanent posted speed limits.
Central District police would also use a plane for the long weekend to monitor traffic flow and identify speeding vehicles.
"Along with the aircraft, our officers will be out keeping the roads safe and anyone we identify doing anything that places other drivers at risk can expect to be caught," Mr White said.
Queen's Birthday weekend officially starts at 4pm on Friday and ends at 6am on Tuesday.
