Addition Climate Subdivisions

Köppen further divided each major divisions (A, B, C, D, E, F, H) into smaller groups based upon precipitation and temperature patterns. These subcategories are as follows:

Second letter add additional divisions based on precipitation pattern

f - wet year-round
s - dry summer season
w - dry winter season
m - monsoon

Third letter (lower case) add additional divisions based in temperature pattern

a - hot summer
b - warm summer
c - cool summer
d - very cold winters

The complete Köppen climates

Af	Tropical Rainforest	No dry season. The driest month has at least 2.40" (6 cm) of rain. Rainfall is generally evenly distributed throughout the year. All average monthly temperatures are greater than 64°F (18°C).
Am	Tropical monsoonal	Pronounced wet season. Short dry season. There are one or more months with less than 2.40" (6 cm). All average monthly temperatures are greater than 64°F (18°C). Highest annual temperature occurs just prior to the rainy season.
Aw	Tropical savanna	Winter dry season. There are more than two months with less than 2.40" (6 cm). All average monthly temperatures are greater than 64°F (18°C).
BSh	Subtropical steppe	Low-latitude dry. Evaporation exceeds precipitation on average but is less than potential evaporation. Average temperature is more than 64°F (18°C).
BSk	Mid-latitude steppe	Mid-latitude dry. Evaporation exceeds precipitation on average but is less than potential evaporation. Average temperature is less than 64°F (18°C).
BWh	Subtropical desert	Low-latitude desert. Evaporation exceeds precipitation on average but is less than half potential evaporation. Average temperature is more than 64°F (18°C). Frost is absent or infrequent.
BWk	Mid-latitude desert	Mid-latitude desert. Evaporation exceeds precipitation on average but is less than half potential evaporation. Average temperature is less than 64°F (18°C). Winter has below freezing temperatures.
Cfa	Humid subtropical	Mild with no dry season, hot summer. Average temperature of warmest months are over 72°F (22°). Average temperature of coldest month is under 64°F (18°C). Year around rainfall but highly variable.
Cfb	Marine west coast	Mild with no dry season, warm summer. Average temperature of all months is lower than 72°F (22°). At least four months with average temperatures over 50°F (10°C). Year around equally spread rainfall.
Cfc	Marine west coast	Mild with no dry season, cool summer. Average temperature of all months is lower than 72°F (22°). There are one to three months with average temperatures over 50°F (10°C). Year around equally spread rainfall.
Csa	Mediterranean	Mild with dry, hot summer. Warmest month has average temperature more than 72°F (22°). At least four months with average temperatures over 50°F (10°C). Frost danger in winter. At least three times as much precipitation during wettest winter months as in the driest summer month.
Csb	Mediterranean	Mild with cool, dry summer. No month with average temperature of warmest months are over 72°F (22°). At least four months with average temperatures over 50°F (10°C). Frost danger in winter. At least three times as much precipitation during wettest winter months as in the driest summer month.
Cwa	Humid subtropical	Mild with dry winter, hot summer
Dfa	Humid continental	Humid with hot summer
Dfb	Humid continental	Humid with severe winter, no dry season, warm summer
Dfc	Subarctic	Severe winter, no dry season, cool summer
Dfd	Subarctic	Severe, very cold winter, no dry season, cool summer
Dwa	Humid continental	Humid with severe, dry winter, hot summer
Dwb	Humid continental	Humid with severe, dry winter, warm summer
Dwc	Subarctic	Severe, dry winter, cool summer
Dwd	Subarctic	Severe, very cold and dry winter, cool summer
ET	Tundra	Polar tundra, no true summer
EF	Ice Cap	Perennial ice
H	Complex zone. Can encompass any of the above classifications due to the mountainous terrain.

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