Why windy wellington

In October, wind speeds averaged 28kmh in Wellington. Baring Head, which was located between Wellington Harbour and Palliser Bay, was often hit with strong winds. On average, gusts exceeded 96kmh for 72 days each year out there. To put that into perspective, Wellington Airport only saw wind speeds exceed 96kmh, on average, 24 days a year.

Castlepoint on the Wairarapa coast was another area with a strong record of very windy days, on average there were days a year with these kinds of excessive wind speeds. A report from NIWA looking at the climate and weather of Wellington explained areas below hill-top level were often spared the strongest wind speeds due to the disturbance of the terrain, however, gust speeds were sometimes comparable with the higher level winds.

To see the effect the wind had on the region, you just needed to look at the permanent eastward lean of larger vegetation in exposed areas. Cities in the United States, Chile and Argentina, for example, all had similarly strong records. In New York, with its thicket of skyscrapers chopping up the wind, plans are being drawn up for a massive offshore wind farm.

Her home state is plagued by tornados, and the high-plains town of Dodge City is the windiest city in the US. There is a long running — and vaguely ironic — debate over this factoid. In Dodge, the average wind speed is 14mph, but Knapp says this speed is almost a constant. But that would be winds dropping down to two or three miles an hour, instead of miles an hour. Besieged residents build wind breaks and plant trees around their homes to break up the wind.

Homes are built with tiny windows on their northern side to block the savage winter gales. Many are actually dug half into the ground. Kansas sits on the battlefront where high pressure systems roll down the Rocky Mountains from Alaska and Canada, crashing into low pressure systems that rise from the Gulf of Mexico.

The difference in pressure causes air to rush violently between regions. Winds can reach speeds high enough to blow a locomotive off the track, says Knapp. Victoria University school of architecture senior lecturer Michael Donn agrees. When he investigated Wellington's relative windiness recently, he couldn't find anywhere else anywhere with a city, at least that compared. It turns out that we're a windy country. We just happen to be at the windiest part of it. Cook Strait and the mountainous landscape on either side of it are to blame for the constancy of the wind.

It has to go either over or around those mountains, Niwa's Mullan says. As for the worst spots to be, Wellington City Council's most recent data divides the city into five levels of windiness. At the peak end of the scale are zones including the hilly parts of the Miramar peninsula; much of Roseneath, Hataitai and Mt Victoria; the stretch from Owhiro Bay through Happy Valley up to Brooklyn; and pockets of Newlands, Johnsonville and Grenada North.

If you want to take yourself up a few hundred metres into much higher wind speeds that flow at much higher levels, then good luck to you. Luckily a row of pine trees blocks off most northerly gales, but she gets the southerly full-on and has to scramble to pull washing and deckchairs inside before they scatter all over her property.

The trees have a downside too. After one massive pine toppled over earlier this year a stone's throw from the house, she's slightly worried more might follow suit.

It's not just suburban areas that have to deal with high winds. To mitigate such conditions, Donn has helped Wellington develop serious building rules around wind over the past 25 years. It's made a difference in the central city, he says. People sit and eat outside in some spots now where once that was preposterous. Ropes were once necessary on an intersection like Taranaki St and Courtenay Place, but changes to nearby buildings have improved the area.