Defining Climate

Taylor Davis & Austin Wood

Annual Averages and Variations

Climatology- Study of Earth's climate and the factors that cause past, present, and future climate changes.

Climate describes the long-term weather patterns of an area.

Normals- Data gathered on daily high and low temperatures, amounts of rainfall, wind speed and direction, humidity, and air pressure that is averaged on a monthly or annual basis for a period of at least 30 years. This data is used to define an area's climate.

Causes of Climate

  • Differences in latitude
  • Topography
  • Proximity to water
  • Global wind patterns


The tilt of Earth's axis causes differences in solar radiation absorption across the globe.

Climate Zones

  • Tropics- The area between 23.5 degrees S and 23.5 degrees N of the equator which receives direct sunlight at a 90 degree angle.
  • Temperate- The area between 23.5 degrees and 66.5 degrees north and south of the equator which receives sunlight from a 45 degree angle.
  • Polar- The areas located from 66.5 degrees north and south of the equator between the poles which receives little direct sunlight from a 30 degree angle.

Air Masses

Two of the main causes of weather are the movement and interaction of air masses. Air masses can vary based on where they originated and how much solar radiation is available where they form. If an air mass forms over land, it will be dry, whereas if an air mass forms over water, it will be moist air. Weather conditions are greatly affected by air masses because they can cause storms, cold weather, or hot weather in a region.