Snow, gale-force winds and heavy rain are expected to batter parts of the South Island today.
But the good news is several centres on the east coast of the country will reach into the low 20s.
An active front, preceded by a strong to gale northwesterly flow is expected to move over the South Island this evening before moving northeast on Monday, MetService said.
"This system should bring heavy rain to the western areas of the South Island and significant snow to the south.
In the south, a heavy snow watch was in place overnight for North Otago, Central Otago, the Southern Lakes and Dunedin until 2pm Monday.
"Snow is forecast to lower to 300m inland overnight Sunday to Monday and to about 500m near the coast, with significant accumulations above 500m."
A snow watch was also in place for Clutha, Southland and Fiordland.
Looking further into the week, a front is expected to move northeast of the South Island tomorrow, before losing some power over the North Island on Tuesday.
"This front brings rain to many parts of the South Island and western parts of the North Island during this time, with lowering temperatures in the south.
"There is a high risk that rainfall accumulations will approach warning amounts about northern Fiordland, Westland, and the Otago and Canterbury headwaters on Monday, with a moderate risk about Buller, the Nelson and Richmond Ranges on Monday, and a low risk about Taranaki, Waikato and the King Country from Monday to Tuesday."
Snow is also expected in the South Island down to 500m on Monday, down to 300m for inland areas.
There is a high risk snowfall accumulations could reach warning amounts above 500m for Fiordland, Southland, Otago and the Mackenzie Basin.
There is also a heavy rain warning today for Westland, Canterbury Lakes headwaters, Otago Lakes headwaters and Fiordland from Sunday morning to Monday morning.
Wind gust are also predicted to reach 120kmh in Fiordland until Sunday evening.
Whangarei: Mostly cloudy, and drizzle at times. Northeast breezes.
High 18C Low 12C
Auckland: Often cloudy, occasional drizzle from late morning until evening. Northeast breezes.
High 17C Low 12C
Tauranga: Mostly cloudy, and drizzle at times. Northerlies.
High 16C Low 11C
New Plymouth: Often cloudy, and light rain at times. Northerlies.
High 15C Low 11C
Napier: Fine apart from early fog. Northerlies.
High 20C Low 10C
Wellington: Cloudy periods, evening drizzle. Northerlies picking up.
High 14C Low 11C
Christchurch: Fine with some high cloud. Strengthening northerlies.
High 21C Low 9C
Dunedin: High cloud increasing. Rain overnight. Brisk northeasterlies, turning southwest overnight.
High 20C Low 7C