Weather: New Zealand to warm up again after coldest temperatures of the year

New Zealand is set to warm back up again after suffering its coldest temperatures so far this year.

MetService says a series of clear and calm conditions caused overnight temperatures to plummet below zero in many places.

"Most notably, Omarama got down to -5degC early on Saturday morning. Dunedin, Invercargill and Alexandra also recorded their lowest temperatures during the weekend," it says.

"Further north, Christchurch, Wellington and Auckland all recorded their lowest maximum temperatures of the year."

But New Zealand should start to see a return to warmer weather as a ridge of high pressure drifts north during Monday and Tuesday.

"This allows a front to approach the South Island, which is expected to begin moving north over the country from Wednesday bringing rain with it," MetService says.

Temperatures on Monday are expected to hit the high teens or early twenties for the upper North Island, while the rest of the country has to make do with mid to high teens.