Land and Resources, Climate
Roaring Forties, southern oceans, wind currents, Southern Alps, westerly winds
New Zealand’s location in the Southern Hemisphere, or south of the equator, means that its seasons are opposite to those in the Northern Hemisphere. The warmest months of summer are January and February and the coldest months of winter are June and July. New Zealand is located in the Southern Temperate Zone, south of the tropics. It has a mild climate with four seasons. Inland areas have cooler winters and warmer summers than coastal areas, where the moderating influence of the ocean creates a more temperate climate.
Temperatures tend to be warmer in the north than in the south; the warmest area is in the extreme northern end of the North Island, and the coldest area is on the southwestern slopes of the Southern Alps. In most of the country, however, there are only minimal climatic differences between north and south. Average low winter temperatures range from 2°C (35°F) in Christchurch, on the South Island’s central east coast, to 8°C (46°F) in Auckland, in the northwest of the North Island. Average high summer temperatures are 23°C (73°F) in Auckland and 21°C (70°F) in Christchurch.
New Zealand is located in the “Roaring Forties” wind belt, an area between latitudes 40° and 50° south where westerly winds sweep across the southern oceans. The prevailing westerly winds bring moisture from the ocean, resulting in heavy rainfall on the western coasts, especially on the South Island. The main divide of the Southern Alps receives the most precipitation in the country. The mountains form a natural barrier to weather patterns from the west; in the eastern rain shadow of the mountains, the westerly winds become warm, dry, and gusty. The east coasts are therefore much drier than the west coasts, and eastern areas of the South Island have some of New Zealand’s sunniest, driest weather. Average annual rainfall in Christchurch is about 638 mm (25 in), compared to 2,906 mm (114 in) in Hokitika, on the west coast. Auckland receives 1,247 mm (49 in) of rain annually.
Although the westerly winds prevail, the eastern part of the country is open to frequent southerlies, wind currents drawing cold air up from the Antarctic. Usually they bring rain, a sharp fall in temperature, and in winter, snow in the mountains. The northernmost extension of the North Island is subject to the tail end of tropical weather systems from the Pacific, and temperatures there are warm year-round, in most places never reaching the freezing point.
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