The Köppen Climate Classification is one of the most widely used systems for categorizing the world’s climates. German climatologist Wladimir Köppen created it in the early 20th century to understand better how temperature and precipitation patterns affect the growth of different vegetation types around the globe. The system divides the Earth’s climates into five main groups, each representing a general climate type. These main groups are further divided into subcategories based on specific patterns of temperature and precipitation. The result is a system that uses letters to represent different climate types, making it easy to categorize and compare regions around the world.
This classification system helps scientists, geographers, and environmentalists understand the different climates around the world and how they influence vegetation, ecosystems, and agriculture. By knowing what kind of climate a region has, we can predict things like rainfall patterns, temperature ranges, and potential for farming. It’s a vital tool for studying climate and weather patterns globally.
The Letter Code
The Köppen system uses a three-letter code to represent each climate type:
The first letter represents the main climate group (A, B, C, D, E).
The second letter provides more details about the precipitation regime (e.g., “f” for no dry season, “w” for dry winter, “s” for dry summer, etc.).
The third letter is used to indicate the temperature pattern (e.g., “a” for hot, “b” for warm, “c” for cool).
For example:
Af (Tropical Rainforest) – “A” for tropical, “f” for no dry season.
Csa (Mediterranean Hot-Summer) – “C” for temperate, “s” for dry summer, “a” for hot summers.
1st (Main Group)
2nd (Precipitation Subgroup)
3rd (Temperature Subgroup)
A (Tropical)
f (Rainforest)
m (Monsoon)
w (Savanna, dry winter)
s (Savanna, dry summer)
B (Dry)
W (Arid desert)
h (Hot)
S (Semi-arid steppe)
k (Cold)
C (Temperate)
w (Dry winter)
a (Hot summer)
f (No dry season)
b (Warm summer)
s (Dry summer)
c (Cold summer)
D (Continental)
w (Dry winter)
a (Hot summer)
f (No dry season)
b (Warm summer)
s (Dry summer)
c (Cold summer)
d (Very cold winter)
E (Polar)
T (Tundra)
F (Ice cap)
Precipitation Subgroups:
f = Fully humid (no dry season)
s = Summer dry (dry in summer, wet in winter)
w = Winter dry (dry in winter, wet in summer)
m = Monsoonal (seasonal rainfall, influenced by monsoons)
S = Steppe (semi-arid, more rain than deserts)
W = Desert (very little rainfall)
Temperature Subgroups:
a = Hot summer (average temperature above 22°C in the warmest month)
b = Warm summer (average temperature between 18°C and 22°C)
c = Cool summer (average temperature between 10°C and 18°C)
d = Extremely continental (cold winters and hot summers)
h = Hot arid (hot deserts)
k = Cold arid (cold deserts)
F = Polar frost (always below freezing)
T = Polar tundra (cool summer, cold winters)
The Five Main Climate Groups:
A – Tropical Climates (Tropical Moist Climates)
Characteristics: These climates are characterized by consistently high temperatures throughout the year, with monthly average temperatures above 18°C (64°F). Precipitation is abundant, often exceeding 1500 mm (59 inches) annually, and the climate typically features distinct wet and dry seasons.
Subtypes:
Af (Tropical Rainforest): No dry season, with rainfall throughout the year. Example: Amazon Basin in South America, Congo Basin in Africa.
Am (Tropical Monsoon): A short dry season, typically between one and three months, with heavy rains during the rest of the year. Example: Coastal regions of South and Southeast Asia, such as parts of India and Southeast Asia.
Aw (Tropical Savanna): A distinct dry season during the winter months, with rainfall occurring primarily in the summer. Example: Sub-Saharan Africa, parts of India and South America.
B – Dry Climates (Arid and Semi-Arid Climates)
Characteristics: These climates are characterized by a lack of sufficient precipitation to support most forms of plant life, typically with less than 250 mm (10 inches) of rainfall annually. These areas experience large temperature fluctuations between day and night and can be hot or cold.
Subtypes:
BWh (Hot Desert): Very hot and dry throughout the year, with extremely low precipitation (less than 250 mm) and high temperatures, especially during the day. Example: Sahara Desert in Africa, Arabian Peninsula.
BWk (Cold Desert): Cold deserts that can have cold winters with some frost or snow, but the total annual rainfall is still below 250 mm. Example: Great Basin in the western United States, parts of Central Asia.
BSh (Hot Semi-Arid): Semi-arid climates with more precipitation than deserts, but still insufficient for widespread agriculture. These areas may have hot summers and mild winters. Example: Sahel region in Africa, parts of Mexico and Australia.
BSk (Cold Semi-Arid): A cooler semi-arid climate, with precipitation more evenly spread throughout the year, but still less than required for extensive vegetation. Example: Great Plains in the United States, parts of Central Asia.
C – Temperate Climates (Mild Climates)
Characteristics: These climates feature moderate temperatures, with warm to hot summers and mild winters. Precipitation is evenly distributed throughout the year or occurs more in the winter months. This group includes areas where crops like wheat, rice, and grapes can be grown.
Subtypes:
Cfa (Humid Subtropical): Hot, humid summers and mild winters, with rainfall throughout the year, often from thunderstorms. Example: Southeastern United States, parts of China, and Japan.
Cfb (Oceanic or Marine West Coast): Mild summers and winters, with a consistent amount of rainfall throughout the year. Often located on the western coasts of continents, especially in temperate latitudes. Example: Coastal regions of the Pacific Northwest (U.S. and Canada), parts of Western Europe (e.g., the UK, France).
Cfc (Subpolar Oceanic): Cooler version of the oceanic climate, found in higher latitudes with cooler temperatures but consistent precipitation. Example: Coastal regions of Iceland, Norway, and parts of New Zealand.
Csa (Mediterranean Hot-Summer): Hot, dry summers and mild, wet winters, common in Mediterranean regions. Example: Southern California, parts of southern Europe (e.g., Italy, Spain, Greece), parts of Australia.
Csb (Mediterranean Warm-Summer): Similar to Csa but with cooler summer temperatures. Example: Coastal regions of California (e.g., San Francisco), parts of Chile, and the Cape region of South Africa.
D – Continental Climates (Cold Climates)
Characteristics: These climates have large temperature differences between summer and winter, with warm to hot summers and very cold winters. They are found in interior regions of continents, far from oceans that might moderate the temperature.
Subtypes:
Dfa (Hot Summer Continental): Hot summers with cold winters, with no dry season. Precipitation is spread throughout the year, but winters are long and harsh. Example: Much of the United States (e.g., Midwest), parts of Europe (e.g., Poland, Ukraine).
Dfb (Warm Summer Continental): Similar to Dfa, but with cooler summers. Winters are still cold and long, but with more moderate summer temperatures. Example: Parts of Canada, the northern United States (e.g., Minnesota, Wisconsin).
Dfc (Subarctic): Extremely cold winters with short, cool summers. Precipitation is low, and winters last for much of the year. Example: Siberia, parts of Alaska, and northern Canada.
Dfd (Severe Subarctic): Very cold and long winters, and short summers, with temperatures often well below freezing during the winter months. Precipitation is generally low. Example: Extreme northern regions of Russia and Canada.
E – Polar Climates (Cold, Ice Climates)
Characteristics: These climates are found at the poles, where temperatures are consistently cold year-round. Precipitation is minimal, and most of it falls as snow. Vegetation is limited, often to mosses, lichens, and low shrubs.
Subtypes:
ET (Tundra): A climate with long, harsh winters and cool summers. Temperatures rarely rise above 10°C (50°F) during the summer. Precipitation is low, but enough to support small, hardy plants. Example: Coastal Arctic regions, parts of Greenland, and northern Canada.
EF (Ice Cap): Extremely cold year-round with temperatures below freezing all year. Precipitation is almost nonexistent, and there is little to no vegetation. Example: Antarctica, Greenland’s ice sheet.
