A fine and settled day is in store for most of New Zealand today, with chilly temperatures bringing frost and snow to some parts.
MetService meteorologist Micky Malibuk said a ridge building over the country will make for mostly calm conditions.
The North Island will have some showers first thing this morning that will quickly clear, bringing fine weather.
About 3cm of snow accumulated on Desert Rd overnight, and will remain on the road this morning.
State Highway 1 between Otaki and Levin was closed last night because of flooding as heavy rain hit the lower North Island. The road has since reopened.
Parts of State Highway 2 on Rimutaka Hill Rd were closed down to one lane because of slips caused by heavy rain in the Tararua Ranges.
Gisborne and Hawke's Bay will have showers that retreat to the coast this morning, which will clear in the afternoon. Strong cold southerlies will also hit the region, however, they will gradually ease throughout the day.
Colder temperatures in the South Island will bring morning frosts, with a chance of afternoon showers in Buller, Westland, Fiordland and Southland.
"Inland Canterbury and Otago hit minus temperatures overnight," Mr Malibuk said. Nelson, Marlborough, Canterbury and Otago will be fine with morning frosts.
In Fiordland and Southland, occasional showers will fall throughout the day, mainly near the south coast but they will become more widespread across Fiordland by mid-morning.
South Islanders are feeling the effects of the cold snap forecast to bring snow to some alpine areas.
The MetService urged motorists in the South Island and on the North Island's Desert Rd to take care with a southerly change bringing snow down to 500m.
Arthur's Pass Alpine Motel owner Fiona Neale said snow began falling close to the alpine settlement between Christchurch and Greymouth mid-afternoon yesterday.
"We had about half an hour of snow down to about 850m, so it's in the treetops."
Maruia Springs Thermal Resort managing director James White said: "It's looking like a winter wonderland at the moment. The temperature has dropped in the last couple of hours. It's definitely winter."
The unusually warm June so far - where Auckland's 19.9C was one of its highest June temperatures recorded - appears to be over.
Duty meteorologist Peter Little said the cold front would be followed by cooler southerlies that would see temperatures plummet to more usual winter levels.
The fronts will bring heavy rain to the upper South Island and Tararua Range, with a low risk of thunderstorms over northern Marlborough and the west of the North Island up to Auckland this evening.
However, a ridge of high pressure making its way towards the country would mean clear skies, little wind and, inland, severe frosts for the South Island.
WeatherWatch analyst Philip Duncan said the week will generally be dominated by westerlies in the lower two-thirds of the country and more high pressure and lighter winds in the north.
Whangarei: Mon 16C, sunny; Tues 18C, sunny.
Auckland: Mon 15C, sunny, chance early shower; Tues 17C, sunny.
Hamilton: Mon 13C, sunny; Tues 16C, sunny.
Tauranga: Mon 15C, sunny; Tues 17C, sunny.
Wellington: Mon 13C, mostly sunny; Tues 15C, sunny.