Köppen climate classification

[7][8] As Köppen designed the system based on his experience as a botanist, his main climate groups represent a classification by vegetation type.

[9][11] Desert and semi-arid climates are defined by low precipitation in a region that does not fit the polar (EF or ET) criteria of no month with an average temperature greater than 10 °C (50 °F).

[10] When it is dominated most of the year by the doldrums low-pressure system due to the presence of the Intertropical Convergence Zone (ITCZ) and when there are no cyclones then the climate is qualified as equatorial.

[17] Some of the places with this climate are indeed uniformly and monotonously wet throughout the year (e.g., the northwest Pacific coast of South and Central America, from Ecuador to Costa Rica; see, for instance, Andagoya, Colombia), but in many cases, the period of higher sun and longer days is distinctly wettest (as at Palembang, Indonesia) or the time of lower sun and shorter days may have more rain (as at Sitiawan, Malaysia).

Among these places, some have a pure equatorial climate (Balikpapan, Kuala Lumpur, Kuching, Lae, Medan, Paramaribo, Pontianak, and Singapore) with the dominant ITCZ aerological mechanism and no cyclones or a subequatorial climate with occasional hurricanes (Davao, Ratnapura, Victoria).

(The term aseasonal refers to the lack in the tropical zone of large differences in daylight hours and mean monthly (or daily) temperature throughout the year.

Annual cyclic changes occur in the tropics, but not as predictably as those in the temperate zone, albeit unrelated to temperature, but to water availability whether as rain, mist, soil, or groundwater.

This climate has a driest month (which nearly always occurs at or soon after the "winter" solstice for that side of the equator) with rainfall less than 60 mm (2.4 in), but at least

[10]: 208–211 Most places that have this climate are found at the outer margins of the tropical zone from the low teens to the mid-20s latitudes, but occasionally an inner-tropical location (e.g., San Marcos, Antioquia, Colombia) also qualifies.

The Caribbean coast, eastward from the Gulf of Urabá on the Colombia–Panama border to the Orinoco River delta, on the Atlantic Ocean (about 4,000 km (2,500 mi)), have long dry periods (the extreme is the BWh climate (see below), characterized by very low, unreliable precipitation, present, for instance, in extensive areas in the Guajira, and Coro, western Venezuela, the northernmost peninsulas in South America, which receive <300 mm (12 in) total annual precipitation, practically all in two or three months).

The length and severity of the dry season diminish inland (southward); at the latitude of the Amazon River—which flows eastward, just south of the equatorial line—the climate is Af.

East from the Andes, between the dry, arid Caribbean and the ever-wet Amazon are the Orinoco River's Llanos or savannas, from where this climate takes its name.

Sometimes As is used in place of Aw if the dry season occurs during the time of higher sun and longer days (during summer).

[1][25] This is the case in parts of Hawaii, northwestern Dominican Republic, East Africa, southeast India and northeast Sri Lanka, and the Brazilian Northeastern Coast.

In places that have this climate type, the dry season occurs during the time of lower sun and shorter days generally because of rain shadow effects during the 'high-sun' part of the year.

Desert areas situated along the west coasts of continents at tropical or near-tropical locations characterized by frequent fog and low clouds, although these places rank among the driest on earth in terms of actual precipitation received, can be labeled BWn with the n denoting a climate characterized by frequent fog.

The average temperature of −3 °C (26.6 °F) roughly coincides with the equatorward limit of frozen ground and snow cover lasting for a month or more.

[40] These climates are in the polar front region in winter, and thus have moderate temperatures and changeable, rainy weather.

[10]: 221–223 Dry-summer climates sometimes extend to additional areas where the warmest month average temperatures do not reach 22 °C (71.6 °F), most often in the 40s latitudes.

[10] Rare instances of this climate can be found in some coastal locations in the North Atlantic and at high altitudes in Hawaii.

This flow is often what brings the frequent and strong but short-lived summer thundershowers so typical of the more southerly subtropical climates like the southeast United States, southern China, and Japan.

These climates are dominated all year round by the polar front, leading to changeable, often overcast weather.

[10]: 226–229 Subtropical highland climates with uniform rainfall (Cfb) are a type of oceanic climate mainly found in the highlands of Australia, such as in or around the Great Dividing Range in the north of the state of New South Wales, and also sparsely in other continents, such as in South America, among others.

Dfa climates usually occur in the high 30s and low 40s latitudes, with a qualifying average temperature in the warmest month of greater than 22 °C (72 °F).

Dsa exists at higher elevations adjacent to areas with hot summer Mediterranean (Csa) climates.

In eastern Asia, Dwa climates extend further south into the mid-30s latitudes due to the influence of the Siberian high-pressure system, which also causes winters there to be dry, and summers can be very wet because of monsoon circulation.

Dsa exists only at higher elevations adjacent to areas with hot summer Mediterranean (Csa) climates.

Dsb arises from the same scenario as Dsa, but at even higher altitudes or latitudes, and chiefly in North America, since the Mediterranean climates extend further poleward than in Eurasia.

ET climates are also found on some islands near the Antarctic Convergence, and at high elevations outside the polar regions, above the tree line.

This classification provides an efficient way to describe climatic conditions defined by temperature and precipitation and their seasonality with a single metric.