The first attempt to classify variations in overall climatic conditions could be traced to Aristotle's ancient though ill informed division of the world into Temperate, Torrid, and Frigid Zones. In the present-day, however, most classifications of world climatic types and world climate maps are based on the famous classification innovated by the German meteorologist and climatologist Wladimir Koppen.
Co-authored with his student Rudolph Geiger and introduced as a wall map in 1928, Koppen's world climate map was updated by Koppen several times in his life-time and modified by later climatologists, the most famous modification being that of late University of Wisconsin geographer Glen Trewartha.
The modified Koppen's world climate map makes use of six alphabets to divide the world into six climatic regions on the basis of average annual precipitation, average monthly precipitation, and average monthly temperature:
- A Type or Tropical Humid
- B Type or Dry
- C Type or Mild-Mid Latitude
- D Type or Severe Mid Latitude
- E Type or Polar
- H Type or Highland Climates
- Type A climates include Wet Equatorial Climate (Af); Tropical Monsoon and trade-wind littoral climates (Am); and Tropical wet-dry climate (Aw)
- Type B climates include Tropical and sub-tropical desert climate (Bwh, part of Bwk); Tropical and subtropical steppe climate (Bsh); and Mid-latitude steppe and desert climate (Bsk, part of Bwk)
- Type C climates include Humid sub-tropical climate (Cfa, Cwa); Mediterranean climate (Csa, Csb); and Marine west coast climate (Cfb, Cfc)
- Type D climates include Humid continental climate (Dfa, Dfb, Dwa, Dwb); and Continental subarctic climate (Dfc, Dfd, Dwc, Dwd)
- Type E climates include Tundra Climate (ET) and Snow and ice climate (EF), and
- Type H climate included the different climates in the highl;ands of the world with their local variations.