Climate

What Is Climate?

Weather changes from day to day. However, the weather in any area tends to follow a pattern throughout the year.

When you describe the weather patterns, you are describing the climate of a region.

Climate is the average weather pattern of a region.

One way to describe a region’s climate is with a temperature-precipitation graph.

What Factors Describe Climate?

• The climate of a region can also be described by some other factors, such as winds, distance from a coast, mountain ranges, and ocean currents.

• The climate zones shown here take all these factors into account.

Another way to describe the climate of a region is by the plants that grow there, such as the desert or tropical rainforest.

What Affects Climate?

I. Latitude

II. Bodies of Water

III. Winds and Ocean Currents

IV. Altitude

I. Latitude• Latitude is a measure of how far north or

south a place is from the equator. The angle of insolation is different at different latitudes. As a result, the temperatures are different at different latitudes.

– Tropical Zone – Near the equator temperatures are high all year. Rainfall is plentiful. At about 30º latitude in each hemisphere are deserts, areas of high temperatures and low precipitation.

– Temperate Zones – In the middle latitudes, summers are warm, and winters are cool or cold. Precipitation may be plentiful.

– Polar Zones – At high latitudes winters are long and cold. Summers are short and warm. Precipitation all year is low.

II. Bodies of Water

• Land and water heat and cool at different rates. Land heats up faster in the sunlight than water does. Land also cools off faster than water. As a result, air temperatures over land are warmer in summer and cooler in winter than they are over oceans at the same latitude.

III. Winds and Ocean Currents

– Wind Patterns – just above and below the equator, the trade winds blow continually. In the middle latitudes are the westerlies. In the polar areas are the easterlies.

– Currents – These winds also move water across the surface of the ocean. As ocean water moves, it moves warm or cool air with it. A warm current, the Gulf Stream, flows up along the east coast. The California Current, a cool current, moves down along the west coast.

IV. Altitude• Altitude is a measure of how high above

sea level a place is. The higher a place is above sea level, the cooler its climate is.

Read pages D88-D91