Climate

North America's climates range from polar to tropical, from dry to extremely rainy. There are many reasons for this wide range, but the more important ones are latitude, elevation, effects of large bodies of water and ocean currents, and prevailing winds. Latitude is largely responsible for the consistently cold climate of Greenland and the Arctic islands, and for the warm climates of much of the West Indies and Central America.

In North America's interior, far from the moderating influence of the sea, the land heats rapidly in summer and cools just as rapidly in winter, causing great seasonal extremes of temperature. In some interior areas winters are more extreme than in polar lands, and summers hotter than in the tropics. In general, precipitation increases south and east, with the maximum amounts along the Gulf Coast.

In coastal areas, especially the Pacific coast of Canada and the United States, seasonal variations are less pronounced because of the moderating effect of the sea. Winds moving over the relatively warm ocean waters bring mild temperatures and moderate to heavy rain. Inland in the south-western United States and northern Mexico, rain decreases and temperatures increase, creating desert and near-desert conditions.

Elevation and exposure to moisture-laden winds are important factors in determining the climates in tropical Mexico, Central America, and the West Indies. Temperatures are high all year, and rainfall is generally greatest on the east coast, reaching maximums in Panama and Belize.