Köppen climate classification


The Köppen climate classification is one of the most widely used climate classification systems. It was first published by the German-Russian climatologist Wladimir Köppen in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system.
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, B, C, D, and E. Each group and subgroup is represented by a letter. All climates are assigned a main group. All climates except for those in the E group are assigned a seasonal precipitation subgroup. 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.
As Köppen designed the system based on his experience as a botanist, his main climate groups are based on what types of vegetation grow in a given climate classification region. In addition to identifying climates, the system can be used to analyze ecosystem conditions and identify the main types of vegetation within climates. Due to its link with the plant life of a given region, the system is useful in predicting future changes in plant life within that region.
The Köppen climate classification system has been further modified, within the Trewartha climate classification system in the middle 1960s. The Trewartha system sought to create a more refined middle latitude climate zone, which was one of the criticisms of the Köppen system.

Overview

The Köppen climate classification scheme divides climates into five main climate groups: A, B, C, D, and E. The second letter indicates the seasonal precipitation type, while the third letter indicates the level of heat. Summers are defined as the 6-month period that is warmer either from April–September and/or October–March while winter is the 6-month period that is cooler.
Group A: Tropical climates
This type of climate has every month of the year with an average temperature of or higher, with significant precipitation.
Group B: Dry climates
This type of climate is defined by little precipitation.
Multiply the average annual temperature in Celsius by 20, then add
If the annual precipitation is less than 50% of this threshold, the classification is BW ; if it is in the range of 50%–100% of the threshold, the classification is BS.
A third letter can be included to indicate temperature. Originally, h signified low-latitude climate while k signified middle-latitude climate, but the more common practice today, especially in the United States, is to use h to mean the coldest month has an average temperature above , with k denoting that at least one month's averages below 0 °C. In addition, n is used to denote a climate characterized by frequent fog and H for high altitudes.
Group C: Temperate climates
This type of climate has the coldest month averaging between and and at least one month averaging above. For the distribution of precipitation in locations that both satisfy a dry summer and a dry winter, a location is considered to have a wet summer when more precipitation falls within the summer months than the winter months while a location is considered to have a dry summer when more precipitation falls within the winter months. This additional criterion applies to locations that satisfies both DS and DW as well.
Group D: Continental climates
This type of climate has at least one month averaging below and at least one month averaging above.
Group E: Polar and alpine climates
This type of climate has every month of the year with an average temperature below.
s are characterized by constant high temperatures ; all 12 months of the year have average temperatures of 18 °C or higher. They are subdivided as follows:

''Af'': Tropical rainforest climate

All 12 months have an average precipitation of at least. These climates usually occur within 10° latitude of the equator. This climate has no natural seasons in terms of thermal and moisture changes. When it is dominated most of the year by the doldrums low-pressure system due to the presence of the Intertropical Convergence Zone and when there are no cyclones then the climate is qualified as equatorial. When the trade winds are dominant most of the year, the climate is a tropical trade-wind rainforest climate.
Examples


Some of the places with this climate are indeed uniformly and monotonously wet throughout the year, but in many cases, the period of higher sun and longer days is distinctly wettest or the time of lower sun and shorter days may have more rain.
Among these places some have a pure equatorial climate with the dominant ITCZ aerological mechanism and no cyclones or a subequatorial climate with occasional cyclones.
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 ground water. Plant response, animal, and human activities are tuned to this 'seasonality'. Indeed, in tropical South America and Central America, the 'rainy season' is called invierno or inverno, though it could occur in the Northern Hemisphere summer; likewise, the 'dry season'.

''Am'': Tropical monsoon climate

This type of climate results from the monsoon winds which change direction according to the seasons. This climate has a driest month with rainfall less than, but at least of average monthly precipitation.
Examples

''Aw/As'': Tropical savanna climate

''Aw'': Tropical savanna climate with dry-winter characteristics

Aw climates have a pronounced dry season, with the driest month having precipitation less than and less than of average monthly precipitation.
Examples


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 also qualifies. Actually, the Caribbean coast, eastward from the Gulf of Urabá on the Colombia–Panamá border to the Orinoco River delta, on the Atlantic Ocean, have long dry periods.
This condition extends to the Lesser Antilles and Greater Antilles forming the circum-Caribbean dry belt. The length and severity of the dry season diminishes inland ; 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.

''As'': Tropical savanna climate with dry-summer characteristics

Sometimes As is used in place of Aw if the dry season occurs during the time of higher sun and longer days. This is the case in parts of Hawaii, northwestern Dominican Republic, East Africa, and the Brazilian Northeastern Coast. In most places that have tropical wet and dry climates, however, the dry season occurs during the time of lower sun and shorter days because of rain shadow effects during the 'high-sun' part of the year.
Examples

Group B: Dry (desert and semi-arid) climates

These climates are characterized by the amount of annual precipitation less than a threshold value which approximates the potential evapotranspiration. The threshold value is calculated as follows:
Multiply the average annual temperature in °C by 20, then add
According to the modified Köppen classification system used by modern climatologists, total precipitation in the warmest six months of the year is taken as reference instead of the total precipitation in the high-sun half of the year.
If the annual precipitation is less than 50% of this threshold, the classification is BW ; if it is in the range of 50%–100% of the threshold, the classification is BS.
A third letter can be included to indicate temperature. Originally, h signified low-latitude climate while k signified middle-latitude climate, but the more common practice today, especially in the United States, is to use h to mean the coldest month has an average temperature above 0 °C , with k denoting that at least one month averages below 0 °C.
Desert areas situated along the west coasts of continents at tropical or near-tropical locations characterized by frequent fog and low clouds, despite the fact that these places rank among the driest on earth in terms of actual precipitation received are labelled BWn with the n denoting a climate characterized by frequent fog. The BSn category can be found in foggy coastal steppes.

''BW'': Arid climate


''BS'': Semi-arid (steppe) climate

In the Köppen climate system, temperate climates are defined as having an average temperature above in their coldest month but below. The average temperature of roughly coincides with the equatorward limit of frozen ground and snowcover lasting for a month or more.
The second letter indicates the precipitation pattern—w indicates dry winters.
The third letter indicates the degree of summer heat—a indicates warmest month average temperature above while b indicates warmest month averaging below 22 °C but with at least four months averaging above, and c indicates one to three months averaging above.

''Csa'': Mediterranean hot summer climates

These climates usually occur on the western sides of continents between the latitudes of 30° and 45°. These climates are in the polar front region in winter, and thus have moderate temperatures and changeable, rainy weather. Summers are hot and dry, due to the domination of the subtropical high pressure systems, except in the immediate coastal areas, where summers are milder due to the nearby presence of cold ocean currents that may bring fog but prevent rain.
Examples

''Csb'': Mediterranean warm/cool summer climates

Dry-summer climates sometimes extend to additional areas typical Mediterranean climates, however since their warmest month average temperatures do not reach they are classified as Csb. Some of these areas would border the oceanic climate, except their dry-summer patterns meet Köppen's Cs minimum thresholds.
Examples

''Csc'': Mediterranean cold summer climates

Cold summer Mediterranean climates exist in high-elevation areas adjacent to coastal Csb climate areas, where the strong maritime influence prevents the average winter monthly temperature from dropping below 0 °C. This climate is rare and is predominantly found in climate fringes and isolated areas of the Cascades and Andes Mountains, as the dry-summer climate extends further poleward in the Americas than elsewhere. Rare instances of this climate can be found in some coastal locations in the North Atlantic and at high altitudes in Hawaii.
Examples
These climates usually occur on the eastern coasts and eastern sides of continents, usually in the high 20s and 30s latitudes. Unlike the dry summer Mediterranean climates, humid subtropical climates have a warm and wet flow from the tropics that creates warm and moist conditions in the summer months. As such, summer is often the wettest season.
The flow out of the subtropical highs and the summer monsoon creates a southerly flow from the tropics that brings warm and moist air to the lower east sides of continents. This flow is often what brings the frequent but short-lived summer thundershowers so typical of the more southerly subtropical climates like the southern United States, southern China and Japan.
Examples

''Cfb'': Oceanic climate

Marine west coast climate

Cfb climates usually occur in the higher middle latitudes on the western sides of continents between the latitudes of 40° and 60°; they are typically situated immediately poleward of the Mediterranean climates, although in Australia and extreme southern Africa this climate is found immediately poleward of temperate climates, and at a somewhat lower latitude. In western Europe, this climate occurs in coastal areas up to 63°N in Norway.
These climates are dominated all year round by the polar front, leading to changeable, often overcast weather. Summers are mild due to cool ocean currents. Winters are milder than other climates in similar latitudes, but usually very cloudy, and frequently wet. Cfb climates are also encountered at high elevations in certain subtropical and tropical areas, where the climate would be that of a subtropical/tropical rain forest if not for the altitude. These climates are called "highlands".
Examples

Subtropical highland climate with uniform rainfall

Subtropical highland climates with uniform rainfall are a type of oceanic climate mainly found in 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. Unlike a typical Cwb climate, they tend to have rainfall spread evenly throughout the year. They have characteristics of both the Cfb and Cfa climates, but unlike these climates, they have a high diurnal temperature variation and low humidity, owing to their inland location and relatively high elevation.
Examples

''Cfc'': Subpolar oceanic climate

Subpolar oceanic climates occur poleward of or at higher elevations than the maritime temperate climates, and are mostly confined either to narrow coastal strips on the western poleward margins of the continents, or, especially in the Northern Hemisphere, to islands off such coasts. They occur in both hemispheres, most often at latitudes from 60° north and south to 70° north and south.
Examples
Cwa is monsoonal influenced, having the classic dry winter – wet summer pattern associated with tropical monsoonal climates.
Examples

''Cwb'': Dry-winter subtropical highland climate

Dry-winter subtropical highland climate is a type of climate mainly found in highlands inside the tropics of Central America, South America, Africa and Asia or areas in the subtropics. Winters are noticeable and dry, and summers can be very rainy. In the tropics, the monsoon is provoked by the tropical air masses and the dry winters by subtropical high pressure.
Examples

''Cwc'': Dry-winter subpolar oceanic climate

Found located mainly above Cwb climates, it is found mainly in isolated locations mostly in the Andes in Bolivia, Peru and Argentina, as well as in sparse mountain locations in Southeast Asia. It is not common.

Group D: Continental/microthermal climates

These climates have an average temperature above 10 °C in their warmest months, and a coldest month average below 0 °C. These usually occur in the interiors of continents and on their upper east coasts, normally north of 40°N. In the Southern Hemisphere, group D climates are extremely rare due to the smaller land masses in the middle latitudes and the almost complete absence of land at 40–60°S, existing only in some highland locations.

''Dfa/Dwa/Dsa'': Hot summer continental climates

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. In Europe, these climates tend to be much drier than in North America. Dsa exists at higher elevations adjacent to areas with hot summer Mediterranean climates.
These climates exist only in the northern hemisphere because the southern hemisphere has no locations that get the combination of hot summers and snowy winters because the southern hemisphere has no large landmasses isolated from the moderating effects of the sea within the
upper-middle latitudes.
Examples
In eastern Asia, Dwa climates extend further south 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.
Examples
Dsa exists only at higher elevations adjacent to areas with hot summer Mediterranean climates.
Examples
Dfb climates are immediately poleward of hot summer continental climates, generally in the high 40s and low 50s latitudes in North America and Asia, and also extending to higher latitudes in central and eastern Europe and Russia, between the maritime temperate and continental subarctic climates, where it extends up to 65 degrees latitude in places.
Dfb examples

Dwb examples
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.
Examples
Dfc, Dsc and Dwc climates occur poleward of the other group D climates, or at higher altitudes, generally between the 55° to 65° North latitudes, occasionally reaching up to the 70°N latitude.
Examples:

''Dfd/Dwd/Dsd'': Subarctic or boreal climates with severe winters

Places with this climate have severe winters, with the temperature in their coldest month lower than −38 °C. These climates occur only in eastern Siberia and very remote areas in Alaska and Yukon. The names of some of the places with this climate have become veritable synonyms for the extreme, severe winter cold.
Examples
In the Köppen climate system, polar climates are defined as the warmest temperature of any month is below 10 °C. Polar climates are further divided into two types, tundra climates and icecap climates:

''ET'': Tundra climate

Tundra climate : Warmest month has an average temperature between 0 and 10 °C. These climates occur on the northern edges of the North American and Eurasian land masses, and on nearby islands. ET climates are also found on some islands near the Antarctic Convergence, and at high elevations outside the polar regions, above the tree line.
Examples
These ET climates are a colder and more continental variants of tundra. They would have characteristics of the ice cap climate, but still manage to see monthly average temperatures above 0 °C :
Examples
Ice cap climate : This climate is dominant in Antarctica and inner Greenland, but also occurs at extremely high altitudes on mountains, above even tundra. Monthly average temperatures never exceed 0 °C.
Examples
The Köppen climate classification is based on the empirical relationship between climate and vegetation. This classification provides an efficient way to describe climatic conditions defined by temperature and precipitation and their seasonality with a single metric. Because climatic conditions identified by the Köppen classification are ecologically relevant, it has been widely used to map geographic distribution of long term climate and associated ecosystem conditions.
Over the recent years, there has been an increasing interest in using the classification to identify changes in climate and potential changes in vegetation over time. The most important ecological significance of the Köppen climate classification is that it helps to predict the dominant vegetation type based on the climatic data and vice versa.
In 2015, a Nanjing University paper published in Nature analyzing climate classifications found that between 1950 and 2010, approximately 5.7% of all land area worldwide had moved from wetter and colder classifications to drier and hotter classifications. The authors also found that the change "cannot be explained as natural variations but are driven by anthropogenic factors."

Other Köppen climate maps

All maps use the ≥0 °C definition for temperate climates and the 18 °C annual mean temperature threshold to distinguish between hot and cold dry climates.

Climate records