It will be no consolation to campers and others trying to have a summer holiday, but there is a reason the weather is so fickle at this time of year.

Like most explanations it is obvious as soon as you hear it, but for years I couldn't work out why summer comes so late to this country and winter can last until Christmas. Then I asked climate scientist Jim Salinger. It was all to do with the temperature of the sea, he said.

Water takes much longer than land to warm up and cool down. Though the sun reaches its zenith in late December, the sea doesn't reach its warmest until late February.

Hence, March is lovely, we are still going to the beach in April and the weather is fairly settled into June.


Conversely, the sun is at its weakest in late June but the sea temperature doesn't reach its coldest point until late August, when it brings winter squalls in spring and gives us indifferent weather to Christmas and even into the new year.

Obviously, slow sea warming is the same all over the world but the effect is pronounced in this country because we are a thin sliver of land in the southern ocean.

Nearly every other populated place on the planet is on or near a continental land mass, which makes weather more settled.

Land not only heats up and cools down faster than water, it gets hotter and colder than the sea. Continental countries in our latitude fry in summer and freeze in winter. We don't. Auckland seldom gets much warmer than 30C and almost never falls below 0C.

But it is wet, especially in spring and early summer. Auckland is the narrowest neck of New Zealand, where two vast oceans nearly meet and two large harbours almost surround the city. It's like an island as tiny as any in the Pacific and equally exposed to sea weather.

The region is warm and wet and lucky to have so much of New Zealand to its south, for its prevailing wind, the sou'westerly that whips across the whole country from the southern ocean, has usually dropped all its moisture by the time it reaches Auckland.

The wind arrives so dry and mild the city hardly notices it.

Most of our frequent rain, Salinger explained, comes from the opposite direction, the northeast. The nor'easterly swings down from the tropics, sometimes on the tail of a cyclone such as those that lashed us before Christmas, and brings the wild clouds and warm misty rain that has deprived us of so many sunny days since Christmas.

If the season runs to form, the clouds will clear in a week or two and sunshine will set in for February.

Remember last February? Probably not. I'm looking at the Herald's front page of February 15. "Hottest month ever," it said. "Hundred-year-old records are tumbling as unrelenting heat sets New Zealand on course for its hottest February ever. Most regions are between 2C and 3C hotter than normal as the strongest La Nina weather pattern in 30 years drives warm air and heavy humidity over the North Island."

Gisborne had seen 36C, Timaru 41C. Auckland had enjoyed a consistent 27C but high humidity had made it feel a few degrees higher.

As late as June 1, we were still enjoying the sun. May, we reported, had been the hottest on record.

I hope all of this helps.

Cicadas know our summer comes late - so did the organisers of the 1990 Commonwealth Games, who scheduled them for the last week of January and first week of February.

But the country still closes down four weeks too soon. Schools go back in the last week of January and by late February, when the sea is reaching its warmest, Super Rugby starts.

It wouldn't be hard to align our holidays to better weather; the Ministry of Education could initiate it. The school year largely decides when the nation takes a break.

The ministry has recently juggled its calendar to divide the year into four school terms and last year it had no problem adjusting dates to provide a holiday during the Rugby World Cup, which must have been scheduled without the slightest regard for New Zealand's weather.

September and October are usually the worst months of our year. By August last year the long, sea-warmed autumn had gone. A polar blast on August 15 gave even Auckland a flurry of snow, three weeks before the start of the cup.

In the event we were lucky. The first week was wet but thereafter the gods were kind. Maybe we are paying them back now.

If we borrowed a bit from our summer sunshine account for an unseasonably warm and settled World Cup, I'd say it was worth it. But then, I'm not on holiday.