Temperatures will drop close to freezing in parts of the country. Photo: 123RF
A cold blast is expected to bring snow down as low as 400 metres above sea level to parts of Te Waipounamu from Monday night.
MetService has issued its first heavy snow watch of the year for the Queenstown Lakes and Central Otago, from midnight until midday on Tuesday.
Road snow warnings have been issued for Lewis Pass, Porters Pass, Lindis Pass and the Crown Range Road.
MetService meteorologist Mmathapelo Makgabutlane said the cold front would bring rain that was expected to fall as snow as low as 400 to 700 metres over southern and eastern parts of the South Island.
Below the snow level, people will experience a sharp drop in temperatures during the day and overnight.
"Christchurch and Wellington City only get a high of 12C on Wednesday, which will likely feel colder due to the wind chill effect from those punchy southerlies over the eastern South Island and lower North Island," Makgabutlane said.
"Overnight temperatures will be near freezing for parts of Southland and Otago into Wednesday morning, and central North Island Thursday morning, so no doubt those winter blankets will come in handy this week."
In the North Island, brief snowfalls are forecast over the mountains on Wednesday and large swells are predicted on the east coast on Wednesday and Thursday.
The Chatham Islands should prepare for periods of rain, gale-force winds and large southwesterly swells on Wednesday and Thursday.
But the bitter days are not expected to stick around, with a ridge of high pressure forecast towards the end of the working week.
"After a dip mid-week, it will certainly be a brighter end to March 2023," Makgabutlane said.