The Rocky Mountains

West of the Great Plains is the Rocky Mountain region. The Rocky Mountains extend from Canada south to New Mexico and Western Texas. The region occupies an area over 1,600 kilometers long, it varies in width between 200 to 600 kilometers. The Rockies stretch from north to south. The Rocky Mountains are much more rugged and much higher than the Appalachians. Plants are greatly affected by altitude. Mountain tops not covered by snow are capped by tundra grasses and mosses.

Intermontane Plateaus

West of the Rocky Mountains lies an area of intermontane plateaus and basins. The term intermontane means "between mountains". The region lies between the Rocky Mountains and mountain ranges along the Pacific coast. Some of the most impressive landscapes in the country are found in the region. The best known is the Grand Canyon.

The Pacific Coastal Ranges

The most western of the physical regions of the conterminous United States is made up of the Pacific coast mountain ranges. Like the Rockies, they extend from Canada in the north to the border with Mexico in the south. It has some of the highest mountains as well as some of the richest farmland in the United States.

Mount Rainier at 4,392 meters above sea level, is in the Cascade Range.

Climate

The United States has areas of all five major climate groups.

Southern Florida has a tropical moist climate. Even in the coldest month of January, temperatures average above 21 degrees centigrade. The area has a growing season that lasts all year long.

North of the Ohio River and east of the Great Plains, there is a moist, cold winter climate. South of the Great Lakes, summers are hot and winters have at least one month of average high temperatures below 0 degree centigrate. East and West of the Great Lakes, summers are cooler and winters are longer.

Most of the Great Plains is under a semiarid climate.

Basins in the intermontane region have a generally dry climate. This climate is found in parts of Nevada, Arizona, and New Mexico as well as in western Texas and southeastern California. Summers are generally hot with cold winters.

The Pacific Coast is under mostly moist mild winter climates of two kinds.

In central and southern California, there is a Mediterranean climate. Summers are dry and winters are cool and rainy.

The climate of Alaska is generally cold over the whole state. The climate of Hawaii is tropical and moist. It receives short periods of rain throughout the year.