Some of the heaviest frosts of the year are forecast to hit this weekend, with experts warning overnight temperatures could drop as low as -8C.
A cold southerly snaking its way up the country is being chased by a large high, which will lock the cold air in and send the mercury plummeting.
- Weather: Significant snow and gales expected as cold front due over New Zealand
- Rugby World Cup 2019: Rain expected to hit during Bledisloe Cup decider
- Large avalanches possible as more significant snowfall predicted in South Island
"Overnight lows tonight may drop as low as -8C in alpine areas. Inland parts through Otago, Southland and Canterbury have the highest risk of frost tonight," WeatherWatch warns.
The weather company is forecasting Queenstown will drop down to -5C on Saturday night, while Alexandra and Cromwell look to drop to around -3C.
On Sunday the risk of frosts spreads to the North Island as the high-pressure system expands, bringing lighter winds and lower temperatures.
"Frosty weather is possible around some parts of Waikato on Monday morning," WeatherWatch says.
"Rural parts of south Auckland are on the borderline where it lifts up to 3C. A slight breeze in the north may keep overnight lows up a few degrees.
"Frosts overnight Sunday/Monday morning will be possible in a number of inland, sheltered, parts of both islands."
Warmer northerlies return on Monday to the South Island and on Tuesday in the North Island.