Weather: New Zealand
Auckland | Christchurch | Wellington
The weather across the two islands of New Zealand isn't especially violent or dramatic, but it does keep you guessing. The band of westerly winds across the South Island is known as the Roaring Forties, and with good reason. Across the planet, there's no other land at this latitude except for Patagonia, so the flow circles the globe with vigour and brings a regular parade of fronts through New Zealand. Since the country lies in the middle of a huge ocean, the fronts are marked less by large temperature changes and more by outbreaks of rain and showers, with snow in the spectacular mountains that run the length of both islands. The quick shifts mean that sunlight can break through a dismal day when you least expect it to.
The north–south span of New Zealand's islands is big – as wide as that from South Carolina to Maine. This means that Auckland, for example, is a few degrees warmer than Christchurch. However, the big players in Kiwi weather are the ubiquitous, moisture-intercepting mountains. Outside of a few leeside areas that get as little as 400mm/16in of precipitation per year, most points in New Zealand see rain or snow at least every 2 to 3 days, with a little more in the winter. West-facing slopes are far wetter than the major cities, especially on the South Island. Hokitika – on the coast just west of Arthur's Pass National Park – averages over 2800cm/110in of precipitation a year, with each month getting a healthy dose. Glaciers and snowfields dot the rugged peaks of the Southern Alps, where total annual precipitation (including snowmelt) exceeds 8000mm/315in. Snow also coats the lower elevations of the eastern South Island a few times each winter. Thunder is a rare event across this maritime land.
Wind is far more of a factor in New Zealand than in Australia. Gales channelled through the Cook Strait keep the people of Wellington hanging onto their hats. To the east of the Alps, strong westerly flow is sometimes forced over the mountains to create a warm, dry fohn-style wind called the norwester. It's a welcome visitor when it breaks up a prolonged spell of sub-freezing cold over snow-covered lowlands. In summer, the same type of downslope wind can trigger unsettling heat on rare occasions. The most spectacular case occurred as the remnants of a tropical cyclone threw energy across the Alps on February 7, 1973. Christchurch and other towns soared to the vicinity of 42°C/108°F, well above the nation's previous record high. Lying closer to the sub-tropics, the North Island is less prone to such gyrations. At sea level the temperature seldom goes below 0°C/32°F or above 30°C/86°F, although frosts are frequent in many areas and the volcanic peaks can get colder still. The eastern lowlands can hit 35°C/95°F with a good downslope wind in summer. Both the North and South islands have a fairly dependable sea breeze that helps keep inland heat from plaguing the coastlines.