1. What is Climate?
What is Climate?

2. Climate is the name for the general conditions of temperature and precipitation for an area over a long period of time.
The climate of any region on the Earth is determined by two basic factors: temperature and precipitation.

3. Factors that Affect Temperature
Latitude, elevation, and the presence of oceans currents are three natural factors that affect the temperature at a particular location.
Latitude is a measure of the distance north and south of the equator.
Elevation or altitude, is distance above sea level. As elevation increases, the air becomes less dense. As elevation increases, the temperature decreases.

4. Ocean currents is a “river” of water that flows in a definite path in the ocean. Warm water warms the air and cold water cools the air. So land areas near warm water currents have warm temperatures and areas near cold water currents have cool temperatures.

5. Factors That Affect Precipitation
The two natural factors that affect the amount of precipitation at a particular location are prevailing winds and mountain ranges.

6. Prevailing Winds is a wind that blows more often from one direction than from any other direction. These winds have a great influence on the climate of regions in their path. Different prevailing winds carry different amounts of moisture. Warm air can hold more moisture than cold air.

7. The amount of precipitation at a particular location is also affected by mountain ranges. A mountain range acts as a barrier to prevailing winds.
The windward side of a mountain, or the side facing toward the wind, receives a great deal of precipitation.
The leeward side of a mountain, or the side facing away from the wind receives little precipitation.

8. Climate Zones
The three major climate zones on the Earth are the polar, temperate, and tropical zones.

9. Polar Zones
Polar climates have the coldest average temperatures. The average yearly temperature remains below freezing most of the time. There is little precipitation in the polar zones.

10. Temperate Zone
In the areas of the temperate zones farther from the equator, snow is common in the winter. The closer to the equator, rain normally falls all year round.

11. Tropical Zones
Tropical zones have high temperatures and high humidity. Precipitation in the tropical zones is usually very heavy during part of the year. These zones have the warmest average yearly temperature.

12. Marine and Continental Climates
Within each of the three major climate zones there are marine climates and continental climates.
Areas with marine climate receive more precipitation.
A continental climate is drier.

13. The Four Seasons
Most places on the Earth have four distinct seasons: winter, spring, summer, and autumn.
The different seasons are caused by the tilt of the Earth’s axis.

14. Changes in Climate
The three natural factors responsible for climate changes are:
1. The slow drifting of the continents
2. Changes in the sun’s energy output
3. Variations in the tilt of the Earth’s axis and the shape of the Earth’s orbit.

15. Human activities which include an increased level of carbon dioxide in the atmosphere can also lead to changes in climate.