A sunny start to the week is not expected to continue, with MetService forecasting rain and dropping temperatures across the country.
Conditions are expected to change from Tuesday as a weather system moves up the island.
Meteorologist Mmathapelo Makgabutlane said rainfall was first expected in the western parts of the South Island.
"That continues to extend across the island, reaching the eastern parts on Wednesday and then eventually reaching the North Island late Wednesday into Thursday."
A heavy rain watch is in place for Canterbury north of Amberley, including the Kaikoura District from 6pm Wednesday to Thursday morning, the ranges of Westland south of Harihari from 5pm Tuesday to Wednesday morning, and Fiordland until 10pm Tuesday.
Some cold air was expected behind that rainy front, Makgabutlane said.
"That will be seen in some snowfalls along elevated parts of the South Island as well as colder temperatures down towards the surface on Wednesday into Thursday and for the rest of the week."
Road snowfall warnings were in place for Lewis Pass, Arthur's Pass and Porters Pass from Wednesday evening.
A strong wind watch is also in place for coastal areas of the KaikÅura District and Marlborough south of Cape Campbell from 11pm Wednesday to Thursday morning.
Temperatures would be coldest in the South Island, with Southland expected to reach a maximum of 10 degrees Celsius and Invercargill 11 degrees on Wednesday, Makgabutlane said.
In the North Island, Wellington was expected to reach a maximum of 13 degrees and Masterton 14 degrees on Thursday, she said.
"As we head closer towards the winter months, we are going to start seeing more and more of these switches to cooler temperatures."
But there were still some warmer temperatures expected before winter arrived, she said.