Much of the country has been plunged into winter with snow falling overnight and temperatures dropping below zero in some places.
Motorists were being warned to take care this morning as icy roads caused difficulties.
Dunedin drivers had already experienced a few minor incidents, police said.
• Severe weather warning for south
A "fair bit of snow" fell across Southland and Otago overnight, MetService meteorologist John Law said, with some "pretty cold temperatures" to match.
"We've still got showers running in towards Southland and also up towards Banks Peninsula, and that's going to catch some more snow showers as we go though daytime here, with snow down to about 200m-300m," he said.
"And we also have some snow up about the top of the Desert Rd on the North Island."
Lake Tekapo dropped to the lowest recorded temperature overnight, falling to -3C.
Snow on the Desert Rd saw temperatures there drop to -1C. Queenstown and Methven fell to a chilly 0.2C and 0.5C respectively.
The plunging mercury levels were "very cold for April", Mr Law said, although they were not unheard of.
"But it is going to be another cold day today," he warned.
Meanwhile, many Aucklanders had a rough night's sleep after thunderstorms arrived at 3.30am and continued until dawn, with squally gales and heavy downpours, WeatherWatch said.
Today would be cold across the country, but the worst of the weather would ease off by this evening, with a much calmer night for many.
The warmth returns on Thursday, WeatherWatch said.
Yesterday, areas of Otago, Clutha, Fiordland and Southland were painted white with snow, as a cold front moved its way up the country.
Down south, chilling temperatures saw people pull their winter gear out of the closet two months early, with a temperature of 4C recorded in Queenstown.
In the North Island, heavy rain brought down more than 300 slips on roads across the Wanganui district.
Councillor Ray Stevens, the council's infrastructure spokesman, said contractors had been working "flat out" to keep roads open.
The New Zealand Transport Agency urged drivers to slow down yesterday, allow for extra travel time and carry chains, as snow and ice affected several inland Otago and Southland highways.
State Highway 6, from Dipton to Garston, the main highway linking Invercargill and Queenstown, was the worst affected by the weather.
Further north, police warned motorists to take care in the wet weather after a series of crashes.
One person was extracted from their car and four others were injured after a vehicle hit a bridge barrier in Whitford early yesterday afternoon.
Emergency services were called to Whitford-Maraetai Rd after the crash about 1pm, in which five people were injured.
Fire communications shift manager Scott Osmond said fire crews managed to free the trapped person fairly quickly.
"It is raining currently and police advise all motorists to exercise extreme caution on our roads," police said.
Police also appealed for motorists to slow down in Waikato after nine crashes in the district yesterday.
A small truck and a car both crashed into a wall on the western side of the Cobham bridge yesterday. No one was injured.
A woman and her 2-year-old child also escaped injury after she lost control of her car on Newcastle Rd in Hamilton and careered into the bottom of a two-storey brick house.
Waikato police Senior Sergeant Pete van de Wetering said motorists were not altering their driving behaviour for the weather.
"It's just people clearly not driving to the conditions and they are severe. We're just appealing to the public to be patient and slow down."
Rural Support Otago co-ordinator David Mellish said despite the harsh conditions, farmers had been well informed of winter blast.
"We've had gale sou'westers with a high wind chill factor, 4-12mm of rain over Otago, snow 300m above, south Otago has snow on the ground, yesterday the temperature was 2-3C ... the power was off for a while," he said on Newstalk ZB this morning.
"But this is a two-day event really, and it's well forecast, farmers had plenty of warning of it."
The rain and snow would help replenish water reserves after a dry summer, he said.
"We've got a very low moisture deficit, any moisture will help, but the cold will actually slow growth and that is quite a concern," he said, because the drop in temperatures had arrived so early.
"Last year our first snow was in May."
Most farmers had found the summer difficult, he said, but they were "very tolerant" and had worked hard.
Beef and Lamb, Federated Farmers, and Dairy New Zealand had worked with farmers to make sure they were prepared and got the help they needed.
"We're trying to make communities resilient and [able to] look after themselves," he said.
Coldest Recorded Temperatures Overnight
Lake Tekapo: -3C
Desert Rd: -1C
Showers and strong southwest easing afternoon. High 16C, low 10C
Auckland: Showers, some heavy, and strong southwesterlies easing afternoon. High 16C, low 10C
Hamilton: Morning and evening showers, fine spells. Southwest. High 15C, low 4C
Tauranga: Morning showers then increasing fine spells. Southwest. High 16C, low 6C
Wellington: Brief morning showers, then fine spells. Strong southerly. High 12C, low 8C
Christchurch: Few showers, mainly morning. Strong cold southwesterlies. High 12C, low 5C
: Fine spells, and a few showers. Southwesterlies. High 20C, low 11C
Auckland: Fine spells, few showers, possibly heavy afternoon. Southwesterlies. High 19C, low 8C
Hamilton: Fine spells, few afternoon showers. Southwest breeze. High 18C, low 2C
Tauranga: Mainly fine, few afternoon showers. Southwest breezes. High 19C, low 7C
Wellington: Fine spells, few afternoon showers. Strong cold southerly. High 14C, low 10C
Christchurch: Showers, clears towards evening. Cold southwesterlies. High 14C, low 3C