Longing for the lazy, hazy days of summer

BY REBECCA THOMSON - THE WELLINGTONIAN

Did summers seem longer and hotter 20 years ago?

One of our readers thinks so. In a letter to the editor, Pamela Stainton recalled hot, dry summers during the 1970s and 80s.

"Am I imagining things or was this summer colder than usual?" she asked.

It turns out that our weather-conscious reader might be at least partially right. The 1980s was an especially hot decade.

National Institute of Water and Atmospheric Research figures show that this summer, temperatures were, in fact, between 0.5 and 1.5 degrees higher than average.

Summers have actually been getting warmer since the 1960s, but there was a spike in temperatures during the 1980s.

The summer period is December 1 to March 1.

During the 1960s, the average temperature during this period was 16.8 degrees Celsius. This decade summer temperatures have averaged 17.3C. During the 1980s, summer temperature averaged 17.7C.

Climate scientist Dr Andrew Tait attributed the hot 1980s to fewer anti-cyclones (highs) to the west of the South Island.

"This weather pattern results in south-westerly to southerly flow over New Zealand, which tends to be cooler," he said.

"In addition, anti-cyclones generally have low moisture content, and that might also explain the higher than average relative humidity observed in Wellington in this decade."

Summertime humidity has risen since the 1960s, when the average was 73.8 per cent. During the 1980s, humidity averaged 78 per cent and this decade humidity was 75 per cent during summer.

January 2008 was of the hottest and sunniest summers. Cyclone Funa brought warm, moist air from the tropics and temperatures soared to 29 degrees during the day, nine degrees hotter than usual.

Wellington had 691 sunshine hours, 15 more than in 2007.

It was also one of the windiest summers, with gale-force gusts up to 130 kilometres an hour hitting the region in January.

Meanwhile, December 2007 was one of the coldest summer months in Wellington since records began more than 70 years ago. The average temperature was 12.9 degrees, 2.4C below normal, and the lowest since 1928.

Severe winds cut power to more than 16,000 homes across the central and lower North Island, and two aircraft landings were aborted and several flights delayed at Wellington airport.

NIWA scientists attributed the cold weather that year to more frequent southerly winds caused by the El Nino climate pattern and below-average sea surface temperatures.