MetService shift meteorologist Lewis Ferris said the cold front over the weekend had brought in a good area of very cold air resulting in below-average temperatures in areas including Hamilton dropping to 1.4C and Taumarunui 0.1C today. The Central Plateau hit negative figures.
Residents should expect similar cold starts tomorrow too.
While snow is expected to fall on Desert Rd and the Napier-Taupō Rd, tonight and tomorrow, it was unlikely to reach towns such as Ohakune.
But the snowfall in the central plateau will be good news for those planning to head to Mt Ruapehu during the school holidays from next week as those areas are expecting a dumping.
Mt Ruapehu is forecasting snow on Turoa on Tuesday and for both Turoa and Whakapapa on Wednesday.
Ferris said showers would continue later into the week, with temperatures warming up and fine weather expected at the weekend.
"If Ruapehu gets some snow, it looks like it will be kind of windy over the next couple of days, but for those who can make it into the weekend they might actually be in for a good day come Saturday."
It was not unusual for snow to fall in September in the central plateau because there were swings in weather systems during the shoulder season.
"It turns out that as soon as they see the lambs turning up in the south and daffodils making their way or flowering, is when we seem to get the snow turning up."
Meanwhile, there are also heavy rain watches in places for Wairarapa, Tararua and the eastern hills of Wellington today. A heavy wind warning is also in place in Hawke's Bay and Wairarapa between 1pm and 11pm tomorrow and for Mahia Peninsular from 7pm tomorrow until 1am overnight.