USA

The United States mainland covers almost 9.5 million sq kms and is bounded in the north by Canada and in the south by Mexico. The mainland comprises 48 states and in addition are the separate states of Alaska to the north-west and Hawaii in the central Pacific. Continental USA can be divided into five main physical areas. East to west are: the Atlantic coastal plain, the Appalachian Mountains, the Interior Plain, the North American Cordillera and the Western Plateau (High Plains).

The climate varies. On the Pacific coast, polar conditions in northern Alaska give way to cool and warm temperate zones further south, with moderate rainfall and temperate desert in southern California. The mountain states (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming) exhibit very varied climatic conditions, determined by local mountain features. Winters in the north are very cold with considerable snowfall. The High Plains have a continental climate and experience summer dust storms and winter blizzards. The Atlantic coast is temperate maritime with temperatures varying according to latitude and heavy snowfall in the north is not unusual. The warmest months are July and August.