The South Island passes can expect rain and snow in the coming days, according to MetService.
In an advisory issued on Sunday, MetService said a low is expected to cross the upper South Island on Sunday night and into Monday, which will bring cold southerlies and heavy snow.
Heavy snow is also likely about the higher roads of the North Island later on Tuesday.
In Lewis Pass, up to 50cm of snow could gather at the upper limits, while Arthurs Pass (up to 40cm), Porters Pass (50cm), Lindis Pass (15cm), Haast Pass (10cm), Crown Range (15cm), Milford Road (10cm) and the Dunedin-Waitati Highway (3cm) could all see snow fall.
There is also heavy snow expected for the Canterbury high country and Kaikoura ranges.
WeatherWatch says the southerly change will "kick in" properly early in the working week.
"On Monday a big portion of the South Island will be 4 to 8degC cooler than usual," a post on its site read.
The start to the year has been the warmest on record.
IN a Facebook post on Saturday, MetService ominously warned, in all-caps, "THE COLD IS COMING".
NZN / Newshub.