MetService meteorologist Mmathapelo Makgabutlane said the conditions may affect families travelling for the school holidays and farmers are warned to take extra care as livestock may struggle in the freezing weather.
"With each front, as it passes, it brings colder and colder air from the Antarctic," she said.
"We've issued road snow warnings from the Dunedin–Waitati Highway (SH1) all the way up to Lewis Pass and a snowfall warning has been issued at Desert Rd, (SH1) so it is something to consider if you are travelling."
It follows a weekend of wild weather across the country. The Auckland Harbour Bridge was once again in the firing line, with wind gusts of up to 110km/h forecast today.
Motorcyclists and drivers of high-sided vehicles were advised to stay off the bridge and use the Western Ring Route on SH16 and SH18, and Waka Kotahi/NZTA said it wouldn't hesitate to close the bridge if necessary.
Metservice recorded 107.8mm of rain in the past 24 hours to Sunday morning in Milford Sound, 130km/h wind gusts in Cook Strait and 1352 lightning strikes from midnight to 11am Sunday.
Showers are expected across the North Island for the rest of the day, possibly heavy in the west.
In the South Island, showers become increasingly heavy, with possible thunderstorms and lightning strikes along the east and the Canterbury plains tonight.
Makgabutlane said thunder had even been recorded in the Lower Hutt this afternoon.
Two severe weather warnings remain in place as the weekend ends, with heavy rain forecast in the ranges of eastern Bay Of Plenty and a strong wind watch up for Hawke's Bay south of Hastings and Tararua District.
Monday morning will dawn with showers in the western North Island, with patches of sunny, dry spells in Northland and Auckland.
The Bay Of Plenty is expected to dry out in the afternoon with some sun, before showers return overnight, Weatherwatch says.
Winds are gusty from the west for most areas, tending strong to gale northwest about the lower North Island from afternoon, especially about Wellington and through Cook Strait.
Rain becomes heavy in the morning for the West Coast, easing to showers around midday as strong west to northwest winds change southwest.
Thunderstorms are possible at times, with hail. Strong to gale cold southwesterlies develop about Southland in the morning, reaching Otago around midday, then Canterbury in the afternoon.
Swells whipped up by strong winds are expected to batter the western North and South islands from tomorrow, picking up swell heights around the west coastlines, Makgabutlane said.
MetService's short forecast
For all of the North Island
Scattered showers, mainly south of Auckland and Bay of Plenty, becoming widespread and heavy at times, with hail possible tomorrow. Thunderstorms possible about coastal areas from Waikato to Kapiti.
Nelson, Marlborough and Canterbury
Scattered showers, some heavy with hail. But mainly fine this afternoon and tomorrow morning. Snow lowering to 400 metres later tomorrow.
Buller and Westland
Showers, some heavy with hail and possible thunderstorms. Snow lowering to 400 metres in Buller and 200 metres in Westland tomorrow.
Clutha, Southland and Fiordland
Showers, some heavy with hail and possible thunderstorms. Snow level lowering to sea level tomorrow.
Chatham Islands
Rain, briefly heavy with possible thunderstorms, turning to showers tonight. More heavy falls with hail and thunderstorms possible tomorrow evening.
MetService's extended forecast
Tuesday
North Island: Showers, especially in the west, easing later and clearing north of Taupo. Snow to 600m about the Central Plateau.
South Island: Showers, falling as snow to 400m but to low levels in the far south. Becoming fine about Westland, Canterbury and Marlborough.
Wednesday
North Island: Isolated showers in the west from Taranaki to Northland, easing. Becoming fine elsewhere.
South Island: Showers in the far south, falling as snow at first. Fine or becoming fine elsewhere. Possible early severe frosts about interior basins.
Thursday
Isolated showers about Northland. Rain about Fiordland, spreading to southern Westland later. Mainly fine elsewhere.
Friday
Rain spreading up the South Island west coast, reaching the lower North Island late.
Early scattered rain about Southland and Otago. Cloud increasing elsewhere.
Chatham Islands
Frequent showers and strong, cold west to southwesterlies, all easing on Thursday.
