Defining Climate

By Alexander, Lane & Richardson, Michael

Annual Averages and Variations

  • Climatology is the study of Earth’s climate and the factors that affect past, present, and future climatic changes.
  • Climate describes the long-term weather patterns of an area.


  • The data used to describe an area’s climate include daily high and low temperatures, amounts of rainfall, wind speed and direction, humidity, and air pressure.
  • The data are averaged on a monthly or annual basis for a period of at least 30 years to determine the normals, which are the standard values for a location.

Limitations of Normals

  • When climatic normals are based on airports Data, they might differ from actual weather conditions in nearby cities.