By Krystal Gibbens of RNZ

A sunny start to the week is not expected to continue, with the MetService forecasting rain and dropping temperatures across the country.

Conditions are expected to change from today 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 Kaikōura district from 6pm Wednesday to Thursday morning, the ranges of Westland south of Harihari from 5pm today to Wednesday morning, and Fiordland until 10pm tonight.

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 Kaikōura 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 10C and Invercargill 11C on Wednesday, Makgabutlane said.

In the North Island, Wellington was expected to reach a maximum of 13C and Masterton 14C on Thursday.

“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.