North America


Pearl Amidst The Ocean


        Latitude, topography, the position of the air masses, and the relationships between land and water tend to control the climates of the continent. In the Pacific Northwest the westerly winds, coming off the Pacific Ocean and striking the Pacific Ranges at right angles, deposit much rain on the windward side of the mountains. The leeward sides are much drier strong evidence of topographic control. In the interior of the continent, climate is much affected by the violently colliding air masses that blow southward from the Arctic and northward from the Gulf of Mexico. The Caribbean Sea and the Gulf of Mexico are charged with the warm waters of the North Equatorial Current. Surface temperatures exceed 27° C all year. Therefore the islands of the West Indies and the neighboring mainland enjoy a hot, humid climate.

        In general, North America is much wetter east of the 100th meridian than to the west. Charleston, S.C., receives 102 centimetres of precipitation annually; Cleveland, Ohio, 79 centimetres; and Omaha, Neb., 64 centimetres. But Denver, Colo., receives only 36 centimetres and Yuma, Ariz., less than 10 centimetres. Most of the precipitation at these stations comes in the summer. In California and the Pacific Northwest much of the precipitation is likely to come in the winter. San Francisco receives slightly more than 51 centimetres of rain annually; 38 centimetres of it fall between December and March. The summer months are dry. Vancouver, B.C., receives 145 centimetres, more than half of it between October and February. A unique feature of the Caribbean and Gulf of Mexico is the hurricane, whose tracks sweep over the West Indies, often striking the mainland between Texas and Florida, North Carolina, and New England.

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