First big snow fall as winter weather strikes South Island

Snow has been falling in South Otago late in the afternoon as a cold snap continues to hit the South Island.

A video sent to the Herald is of snow falling at 4.30pm at Crookston, just north of Tapanui and settling on the ground.

The rural settlement is 229 metres above sea level on State Highway 90 and 6km east of Herriot.

MetService is forecasting strong westerlies in the area with temperatures down to below 4C overnight, with more rain and snow through the night.

Snowfall in the Southern Alps between Porters Pass and Arthur's Pass on State Highway 73. Photo / George Heard

MetService had forecast snow to 500m in Southland, Clutha, Dunedin and Queenstown, and down to 800m in Canterbury, which could impact alpine villages and passes.

Snow was falling heavily at Mt Hutt skifield, Porters Alpine Resort in Canterbury, and Cardrona, the Remarkables and Coronet Peak in Central Otago during the day.

Snow falling at Cardrona Alpine Resort. Photo / Supplied

MetService had issued road snowfall warnings for Crown Range Rd, Milford Rd, Porters Pass, Lewis Pass and Arthur's Pass for the next 24 hours.

Snow showers are expected to affect Arthur's Pass with 1-3cm of snow near the summit overnight.

On Porters Pass snow will affect the high part of the road with 1-2cm near the summit and lesser amounts down to 800m.

Snow falling at Mount Hutt Ski Area, Canterbury. Photo / Supplied

Snow is also expected at the top of the Lewis Pass with 1-2cm near the top.

"This will be the lowest snow many have seen so far this year," MetService said.

Temperatures have also dropped considerably in the South Island, with Christchurch hitting zero overnight and forecast to have 14C on Saturday.

For Saturday a high of 10C is forecast in Dunedin and Queenstown.

Temperatures at Aoraki/Mt Cook are set to dip to -3C overnight and 9C on Saturday.

"We could be paving the way for the first significant snowfall of the year as we round out the week," MetService meteorologist Angus Hines said.

Coronet Peak base. Photo / Supplied

Large waves forecast

Heavy swells are also expected to hit some parts of the country.

Boaties near the Foveaux Strait are being warned of high swells, poor visibility and "very rough" seas between Thursday and Saturday, before easing on Sunday.

"Large swell waves and dangerous coastal conditions are expected in the western marine areas of both the North and South Island from Thursday," MetService said.

"Combined waves are forecast to reach 6m for the western South Island later on Friday."