Forecasters last night withdrew warnings of thunderstorms.

MetService had issued a severe thunderstorm watch for Northland, Great Barrier Island, Coromandel and the Bay of Plenty, valid until 10am today but that was dropped last night.

It has also issued a severe weather watch for Otago and Canterbury, as it expects snowfall in these areas.

Weather ambassador Bob McDavitt said a howling wind from the Tasman Sea was moving across northwestern parts of the North Island last night and was expected to reach Bay of Plenty this morning.

"This active front will bring squally showers, which includes the possibility of dangerous gusts, maybe tornadoes, on the northern coasts."

The front is expected to move quickly over the North Island before clearing East Cape by noon today. Some sun may peak through the gloomy weather this afternoon, but bouts of rain are expected throughout the weekend.

"With thunderstorms you don't tend to get heavy rain but strong winds. But it will be squally on and off in the North Island."

Mr McDavitt said the unsettled weather could create hazardous driving conditions, especially with extra travellers on the road for the start of school holidays.

Weatherwatch analyst Philip Duncan said conditions would be poor for skiers, but heavy snowfall at all ski fields would create promising conditions when the weather became drier next week.

He said some snowfall was expected in Otago, Canterbury, Kaikoura, and the higher regions of Wairarapa and Hawkes Bay.

But cheer up, the thaw is coming. Two unseasonably cold months will soon give way to temperatures more in line with a normal winter and spring, say forecasters.

May was the coldest recorded in many parts of New Zealand and June was not far behind, National Institute of Water and Atmospheric Research (Niwa) climate scientist Georgina Griffiths said yesterday.

In an average year, the coldest day comes during the first two weeks of July. But this year the cold snap started early, so the coldest day was probably already over, she said.

Ms Griffiths said June was cold, frosty and sunny for most of the country with average daily high temperatures for the month between 1.5C and 2.5C below normal.

Temperatures would switch to more normal patterns for July, August and September, she said, except in Canterbury and Eastern Otago which would remain chilly.

The cold and sunny weather had largely been caused by "big fat highs" sitting over the country and refusing to budge.

As a result, the average maximum daily temperature in Auckland for June was the second lowest in 50 years - 13.6C.

Several places recorded their lowest June average minimum daily temperatures: Warkworth, Whangaparaoa, Port Taharoa (coastal Waikato), Turangi, Paraparaumu, Wellington, Wanganui and Banks Peninsula.

June also brought several extreme weather events.

Thick fog affected Auckland last Saturday, followed by thunderstorms, lightning and heavy rain the next day. A civil defence emergency was put in place in Gisborne on the 30th, as rain swamped roads and threatened to cut off about 500 people in the East Coast town of Te Karaka.

Of the six main centres, Dunedin was the coldest and driest, Auckland the warmest, Tauranga the wettest, and Hamilton the sunniest.