Physical Geography

Like many other island chains in the Pacific, the islands of New Zealand are the exposed tops of mountains rising from the ocean floor. Some of the mountains on the North Island are of volcanic origin. The country lies astride the Pacific Ocean belt of recent mountain building and volcanic activity. Earthquakes occasionally occur, especially in the North Island, but few are destructive.

The North Island is fringed in places by coastal lowlands, particularly in the north and the southwest. Prevailing elsewhere are hills, plateaus, and mountains. The chief mountainous section is a chain of ranges in the east, running northeast-southwest from East Cape to the city of Wellington. Among its principal ranges are the Tararua, Ruahine, Huiarau, and Raukumara. Here, peaks generally rise 4,000 to 5,000 feet (1,200 to 1,500 m) above sea level.

The interior of the North Island consists largely of a volcanic plateau. Among its diverse landforms are the active volcanoes of Ruapehu, Ngauruhoe, and Tongariro, which range in height from 6,500 to 9,200 feet (1,980 to 2,800 m). To the west, near the coast, is Mount Egmont, a dormant volcanic cone reaching 8,258 feet (2,517 m).

The South Island is much more mountainous than the North. Along the west coast runs a massive mountain rampart. In the central part a narrow coastal lowland is fringed by the ice-capped Southern Alps. Here stands Mount Cook, at 12,349 feet (3,764 m) New Zealand's highest peak. Nearby is Tasman Glacier, largest of the Alps' numerous glaciers. The mountains continue to the north as the Victoria, Spenser, St. Arnaud, Tasman, Richmond, and Kaikoura ranges, and to the south as the Young, Richardson, Humboldt, and Livingstone ranges. Deep, glacier-cut fjords extend far inland along the southwest coast. The South Island's principal lowland is the Canterbury Plains along the east coast.

Nearly all of New Zealand's rivers are relatively short, swift, and unfit for navigation. They are, however, well suited to the development of hydroelectric power. In the North Island the longest rivers are the Waikato and the Wanganui; in the South Island, the Clutha and the Taieri. Taupo is the largest of the country's many lakes. It lies in the North Island's volcanic plateau, an area also known for its bubbling hot springs and spectacular geysers. Flanking the South Island's mountainous backbone are numerous elongated glacial lakes, including Te Anau and Wakatipu.

The inhabited areas of New Zealand have a temperate climate, with mild winters, warm to cool summers, and ample rainfall throughout the year. Among dominant climatic influences are New Zealand's middle-latitude location in the path of westerly winds and storms, its position in the midst of a vast ocean, and the topography of the land.

Temperatures at sea level are moderate throughout the year. Averages for January (the warmest month) and for July (the coldest) are about 68° F. (20° C.) and 52° F. (11° C.) at Auckland in the north; 63° F. (17° C.) and 46° F. (8° C.) at Wellington, in the central part; and 57° F. (14° C.) and 41° F. (5° C.) at Invercargill, in the south. Night frosts occur in winter in many lowland areas, particularly in the south, but snow rarely falls except in the mountains and their foothills.

Rainfall is heaviest in mountains exposed to the direct sweep of the westerly and northwesterly winds. In the Southern Alps rainfall may be as much as 300 inches (7,620 mm) a year. On the leeward slopes and on most of the lowlands, it generally averages between 25 and 60 inches (635 and 1,520 mm), depending on location. Only a small, inland area in the southern part of the South Island receives as little as 13 inches (330 mm) a year.