 Map Pacific Pacific Islands lie within the rainy tropics or the humid subtropics. In such areas there are no abrupt seasonal changes as occur in regions of temperate climate. Temperatures typically average close to 27 C (80 F) most of the year. At higher elevations, temperatures typically drop at the rate of 1.7 C (3 F) for every rise in elevation of 300 m (1000 ft).
In parts of the central and western Pacific, monsoon climates prevail. In monsoon climates, moisture-bearing winds reverse direction once a year, creating a distinct wet season and a dry season. Because of monsoon conditions and differences in elevation, amount of rainfall, seasonal and annual, varies greatly from island to island and even on different parts of larger islands. The windward (usually eastern) slopes of the high islands sometimes receive as much as 6400 mm (250 in) of rainfall annually. The leeward (usually western) slopes of these islands are relatively dry. Many coral islands are arid or semiarid because little moisture falls as air masses pass over low-lying elevations. In recent years, most notably in the early 1980s and late 1990s, an oceanic and atmospheric phenomenon called El Nino brought great aridity to parts of the Pacific Ocean.
In the area from about 30 north of the equator to about 30 south of the equator, the westward-moving trade winds prevail. Centuries ago these steady winds carried the sailing vessels of European traders, hence their name. Where the northern and southern trade winds meet near the equator they cancel each other out, creating the doldrums, a region of little or no wind more formally called the intertropical convergence zone (ITCZ).
The western Pacific is also a breeding ground for tropical cyclones, which are called typhoons in some areas and hurricanes in others. North of the equator most such storms occur between July and November. South of the equator the stormy season begins about November and ends about March. The heavy wind and rains brought by these storms often cause devastating loss of life and property.
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