Duty forecaster Larissa Marintchenko said the areas most affected were Whanganui-Manawatu, Kapiti Coast and Auckland.
The thunderstorms, which came off the Tasman Sea at around 7pm yesterday, pelted West Auckland with larger than normal hail.
WeatherWatch.co.nz reported large hail, which was caused by towering clouds crossing the city with thunderstorms, slamming West Auckland suburbs as it came off the sea and crossed over the Waitakere Ranges.
The bad weather is set to continue around the country for the next two days with motorists on the road for the long weekend urged to take care.
Last night temperatures dropped to 4C in the South Island and 10C in the North Island.
In the South Island, Cardrona Alpine Resort has officially opened its doors but at this stage only for gondola rides and sledding.
It is expected to be open to skiers and snowboarders later in the week when the new snow has been groomed.
Cardrona Alpine Resort communications executive Jen Houltham said they had 10cm of new snow last night and it was still falling this morning.
"It's like winter has just flicked on the switch."
Your weather today
Northland, Auckland, Waikato & Bay Of Plenty
Showers with some heavy hail and thunder. In the eastern parts of the Bay Of Plenty there may be some sun, but showers will likely push through at times and there is a chance of small hail. Blustery west to southwesterly winds.
Highs: 13-15C
Western North Island (including Central North Island)
Showers with hail move through late afternoon / evening as the northwesterly changes southwest. Snow flurries likely about higher parts of the Central Plateau from afternoon. Conditions ease at night.
Highs: 5-13C
Eastern North Island
Mostly sunny with breezy west to northwesterly winds, some rain for southern Wairarapa. This rain spreads further north into Wairarapa in the afternoon as southwesterly winds strengthen, and gales are likely about the coast. In Hawke's Bay and Gisborne cloud increases in the evening and winds tend more southwest.
Highs: 12-16C
Wellington
Areas of rain, heavy at times with small hail especially afternoon as westerlies change strong to gale southerly.
High: 11C
Marlborough & Nelson
Showers, clearing in the afternoon but staying mostly cloudy. Fresh southwester, strong to gale-force winds about eastern coastal Marlborough.
Highs: 10-12
Canterbury
Morning rain, possibly heavy then easing afternoon to showers with a risk of small hail and snow flurries lowering to 500m. Fresh cold southwesterlies, strong to gale about Banks Peninsula in the morning then easing.
Highs: 6-8
West Coast
Mostly sunny for South Westland, North Westland sees some rain or showers then clearing early afternoon. Winds cool from the south.
Highs: 10-13
Southland & Otago
Showers about Southland with small hail possible and snow flurries to 300m by midday. Otago has a dry morning with some sun possible, showers and a risk of small hail moves in late morning with snow flurries possible to 300m by evening. Fresh cold south to southwesterly winds. Conditions ease at night for Southland and Central Otago.
Highs: 6-8C
