Köppen climate classification
The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. The five main groups are "A" (tropical), "B" (dry), "C" (temperate), "D" (continental), and "E" (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the "E" group are assigned a seasonal precipitation subgroup (the second letter). For example, "Af" indicates a tropical rainforest climate. The system assigns a temperature subgroup for all groups other than those in the "A" group, indicated by the third letter for climates in "B", "C", and "D", and the second letter for climates in "E". For example, "Cfb" indicates an oceanic climate with warm summers as indicated by the ending "b". Climates are classified based on specific criteria unique to each climate type.
Continental climate
Most such areas fit Köppen classifications of Dfa, Dwa (cold winters, hot summers; "w" indicating very dry winters characteristic especially of China) or Dfb or Dwb (cold winters, warm summers, same distinction for winter dryness). Dry summer continental climates (Dsa and Dsb) exist in high altitude areas near Mediterranean climates. In some cases, the semi-arid climate classification of BSk can also be considered to be continental as long as it has cold winters. The definition of this climate regarding temperature is as follows: the mean temperature of the coldest month must be below and there must be at least four months whose mean temperatures are at or above .