The Köppen climate classification system is one of the most widely used in the world. It was first created by German-Russian climatologist Wladimir Köppen in 1884. Later, the climatologist Rudolf Geiger introduced some changes to the system, which is sometimes called the Köppen–Geiger climate classification system.
This classification system segregates zones 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 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.
Group A: Tropical Climates – This type of climate has every month of the year with an average temperature of 64.4°F (18°C) or higher, with significant precipitation.
Group B: Dry Climates – This type of climate is defined by little precipitation.
Group C: Temperate Climates – This type of climate has the coldest month averaging between 32°F (0°C) (or 27°F (−3°C)) and 64.4°F (18°C) and at least one month averaging above 50°F (10°C). For the distribution of precipitation in locations that both satisfy a dry summer (CS) and a dry winter (CW), a location is considered to have a wet summer (CW) when more precipitation falls within the summer months than the winter months while a location is considered to have a dry summer (CS) when more precipitation falls within the winter months.
Group D: Continental Climates – This type of climate has at least one month averaging below 32°F (0°C) (or 27°F (−3°C)) and at least one month averaging above 50°F (10°C).
Group E: Polar and Alpine Climates – This type of climate has every month of the year with an average temperature below 50°F (10°C).