Ch. 26.2 Climate Zones

Three main climate zones on earth; tropical climates around the equator, middle latitude climates, and polar climates.

Tropical Climates Avg. monthly temp. of at least 18o C year round. Different climates within climate zones based on annual precipitation. Tropical Rain Forest—within 5 to 10 degrees of the equator; dense vegetation, over 250 cm of rain a year, yearly temperature range of about 3 degrees C.

Tropical Desert Climate—20 to 30 degrees N. and S Tropical Desert Climate—20 to 30 degrees N. and S. latitude; influenced by sinking, warming, dry air; annual rainfall less than 25 cm.

Tropical Savanna Climate—between tropical rain forests and tropical deserts. Shifting precipitation belts result in wet summers and dry winters. Open grasslands with scattered trees and shrubs.

Polar Climates Average monthly temp. never higher than 10 degrees C. Occur between 55 degrees latitude and the poles. Subarctic Climate—between 55 and 65 degrees N. latitude. Yearly precipitation of 25 to 50 cm.

Evergreen forests can grow due to low evaporation. Severe winters and short summers. Large annual temperature range.

Tundra Climate—named for tundra vegetation…mosses, lichens, small flowering plants…no trees. Lower temperature range due to moderating influence of nearby oceans. Warmest months average only 4 degrees C. 25 cm precipitation yearly, mostly snow.

Middle Latitude Climates Latitude ranges from contiguous United States to southern Canada. Uneven precipitation in different regions result in several different climates. Marine West-Coast Climate—40 to 60 degrees N. latitude in Pacific NW. Cool moist air from the ocean causes 60 to 150 cm precipitation. Temp. range from 7 to 20 degree C.

Mediterranean Climate—between 30 and 40 degrees latitude Mediterranean Climate—between 30 and 40 degrees latitude. Wet winters and dry summers. 40 cm avg. precipitation. Temp. range from 14 to 21 degrees C. Middle-Latitude Desert—less than 25 cm precipitation, and cold winters. Shrubs and cacti. 35 to 50 degrees N. latitude.

Steppe Climate—same latitude as mid latitude deserts, but at higher elevations. 25 to 50 cm precipitation / yr. Grass type vegetation, and high temp. range.

Humid Continental—warm humid summers with very cold winters Humid Continental—warm humid summers with very cold winters. Violent weather conditions due to colliding air masses. Humid Subtropical—influenced by moist ocean air in summer. Heavy rains and hurricanes. Southeast USA.