Temperatures are expected to drop to freezing or below this week as Southern Ocean winds blow over the country.
A low pressure system is expected to continue to bring showers and some clouds along the eastern and lower parts of both islands, which would influence temperatures.
South Island inland areas could even see temperatures in the negative, MetService meteorologist Mmathapelo Makgabutlane said.
Most of the South Island was forecast to wake up to single digit temperatures on Wednesday, with Blenheim, Queenstown, Christchurch and Timaru expected some of the coldest areas.
For the remaining days this week, Christchurch's low temperatures range from -4C on Thursday to 1C on Wednesday. For Timaru, the low range is from -3C to -1C, for Blenheim -2C to -1C, and for Queenstown -4C to 2C.
A high temperature of 4C on Thursday in Wanaka was about four degrees below average, MetService said on its X page.
"Still a long way off the coldest maximum of -1.1°C at that station."
Cool winds from the Southern Ocean are going to keep temperatures on the chilly side this week
— MetService (@MetService) July 2, 2024
It is winter after all, but a high temperature of 4°C on Thursday in Wanaka is about four degrees below average.
Still a long way off the coldest maximum of -1.1°C at that station! pic.twitter.com/60Avv1Hi8s
In the North Island, the coldest temperatures could be in Taupō with a low of -3C on Wednesday and -1C from Friday to Sunday, Rotorua with a low of -1C on Wednesday and 0C Thursday, Saturday, and Sunday, and Hamilton with a low of -1C on Thursday and 0C on Wednesday, Saturday, and Sunday.
The low pressure system was also expected to continue to cause rough sea conditions over the next day or so, Makgabutlane said.
"Combined wave heights around the eastern parts of both islands could be around four to six metres, so if you are planning on being near the coast over the next day or so do definitely take extra care around that."
Earlier on Wednesday, large swells forecast for the Cook Strait prompted Bluebridge to cancel some ferry sailings. The Interislander has also cancelled all its sailings from Tuesday night through to Thursday morning.
The low pressure system was expected to be moving away on Thursday, and a high pressure ridge building things would be looking more settled than the start of the week.
"By the end of Friday, however, we are expecting this next weather system to start making its way, may be a bit of a showery start to the weekend down south."