The MetService is urging motorists in the South Island and Desert Rd to take care as a cold southerly brings snow down to 500m in places.
While the dusting - between 5cm and 10cm - won't arrive in the North Island until the early hours of tomorrow, the MetService says temperatures are currently quickly switching from mild to cold as the southerly makes its way up from the bottom of the South Island.
Duty meteorologist Peter Little says the front has just hit Christchurch which has already reached its high temperature of 13C for the day, and is currently sitting on 11C, but it will plummet well into single digits this afternoon.
"The southerly that we've got moving northwards is currently over the South Island approaching Christchurch, that's going to see a return of some cooler temperatures and also bringing some snow with it."
The unusually warm June temperatures - where Auckland's 19.9C was one of its highest June temperatures recorded - are now coming to an abrupt halt with temperatures due to plunge overnight.