Wet autumn, foggy winter with a few snowstorms

A wet autumn and a settled start to winter has led to the cold season's foggy debut - a total of 10 fog days since the start of June saw hundreds of planes grounded and travel plans disrupted.

In the first 11 days of July there were four when fog affected flights - compared with just six in all of June, said Niwa meteorologist Ben Noll.

"The frequent fogs so far during winter 2017 have been a result of a generally wet autumn, followed by settled conditions during early winter with long clear nights and light winds.

"During June we had higher pressure than normal reaching New Zealand...when you have high pressure you have light winds, more clear skies, clearer nights than usual, general tranquillity, all conditions that lead to the development of fog."

He said despite the blustery wet and warm start to the year temperatures had plateaued to near average and rain was at the lower end of normal. In Auckland it was the driest June on record since records began in 1909.

"This winter has been less mild, but has not been extremely cold.

"Auckland, near average, so far in July temperatures near average, pretty ho hum, pretty boring start to winter if you will. But going to get more active this week."

But it may have been the calm before the storm - as this week saw 7m waves forecast for Cook Strait and hail, snow and ice in what was dubbed the biggest winter storm of the year.

While the snow did not reach the northern parts of the country, the north was not immune to the cold snap, with Auckland seeing its coldest temperature so far this year - only just managing to reach double digits with a high of 10 degrees.

But Noll said the end of July was looking a lot milder.

"The cold snap is grabbing all the headlines for a bit, but give it a week or two and it might be a thing of the past."

Heading into late July and early August, milder than average conditions are expected to prevail and an active Tasman Sea may produce frequent rain storms.

MetService meteorologist Angus Hines said it was important to remember we were not fully into winter yet.

"New Zealand doesn't get the coldest temperatures till July and August, so plenty of winter to come. So far June and July have been relatively uneventful weatherwise, chilly in places, but not too many polar outbreaks which brings the stow and strong southerly winds."

He said the past week had heralded the arrival of a "more deep winterly feel".

Fast weather facts

• Auckland saw the driest June on record this year with 48mm of rain recorded at the airport- just 44 per cent of normal
• It was the second-wettest January to June period on record for Auckland with 806mm of rain fallen across the first six months of the year
• January this year saw the wettest start to the year on record at Whangaparaoa with 182mm of rain
• Nationwide average temperature in June 2017 was 8.8°C - 0.2°C above the long term June average
• In June 2016 nationwide average temperature 10.2°C - the third warmest June since records began in 1909
• January - June 2017 ranked the 39th warmest first half of the year since records began with an average temperature of 13.8°C
• Four out of the first 11 days in July had fog that affected flights; compared with six days in all of June where flights were affected by fog

Source: Niwa