text: Berg climate classification Köppen climate classification – most widely used in the 1954 Köppen–Geiger variant
  Holdridge life zone classification – relatively simple
  Lauer climate classification
  Strahler climate classification
  Thornthwaite climate classification
  Trewartha climate classification – 1967 modification of Köppen
  Troll climate classification
  Vahl climate classification
  Zhou climate classification (zh)
  Bergeron and Spatial Synoptic
  The simplest classification is that involving air masses. The Bergeron classification is the most widely accepted form of air mass classification. Air mass classification involves three letters. The first letter describes its moisture properties, with c used for continental air masses (dry) and m for maritime air masses (moist). The second letter describes the thermal characteristic of its source region: T for tropical, P for polar, A for Arctic or Antarctic, M for monsoon, E for equatorial, and S for superior air (dry air formed by significant downward motion in the atmosphere). The third letter is used to designate the stability of the atmosphere. If the air mass is colder than the ground below it, it is labeled k. If the air mass is warmer than the ground below it, it is labeled w. While air mass identification was originally used in weather forecasting during the 1950s, climatologists began to establish synoptic climatologies based on this idea in 1973.