Why does Brazil’s rainforest and India’s monsoon coast both count as “tropical,” yet feel so different on paper? Climate scientists solved this with a single coded system.
This article covers Koeppen’s scheme for classifying world climates — the five main groups, the letter codes, and where each climate type is actually found.
🏛️ Must Know
Three Ways to Classify Climate
- Empirical Classification This groups climates using observed data, mainly temperature and precipitation. It does not ask why a climate behaves that way, only what the numbers show.(NCERT 11)
- Genetic Classification This groups climates by their causes instead of their numbers, such as the air masses or wind belts that produce them.(NCERT 11)
- Applied Classification This is built for one specific purpose, such as classifying climate for farming or for building design.(NCERT 11)
- Koeppen’s Scheme V. Koeppen built the most widely used empirical scheme in 1918. He linked specific temperature and precipitation values to the natural vegetation they support.(NCERT 11)
Koeppen’s Five Climate Groups
- A – Tropical The coldest month still averages 18°C or higher. Capital letters A, C, D and E all mark humid climates.(NCERT 11)
- B – Dry Here, potential evaporation exceeds precipitation. B is the one group marking dry climates, not humid ones.(NCERT 11)
- C – Warm Temperate The coldest month averages between minus 3°C and 18°C. These are the mid-latitude climates.(NCERT 11)
- D – Cold Snow Forest The coldest month averages minus 3°C or below. This group only occurs in the Northern Hemisphere’s large land masses.(NCERT 11)
- E – Cold Every single month averages below 10°C. E climates sit at the highest latitudes.(NCERT 11)
- H – Highland This climate is cold simply because of elevation, not latitude. It can appear at any latitude wherever mountains rise high enough.(NCERT 11)
- Small-Letter Codes Small letters mark seasonality and severity within each group: f means no dry season, m means a short monsoon-style dry season, w means a winter dry season, and s means a summer dry season.(NCERT 11)
- Dry-Climate Codes Within Group B, S marks a steppe or semi-arid climate and W marks a true desert climate.(NCERT 11)
📘 Good to Know
Tropical Humid Climates: Af, Am, Aw
- Group A Basics Tropical humid climates sit between the Tropic of Cancer and the Tropic of Capricorn. The sun stays overhead year-round and the ITCZ keeps the air hot and humid.(NCERT 11)
- Af – Tropical Wet Found near the equator, in the Amazon Basin, western equatorial Africa, and the East Indies islands. Rain falls almost every month, and daily temperatures stay between 20°C and 30°C.(NCERT 11)
- Am – Tropical Monsoon Found across the Indian subcontinent, north-eastern South America, and northern Australia. Rain is heavy in summer and winter stays dry.(NCERT 11)
- Aw – Tropical Wet and Dry Found north and south of the Af zone, such as around the Amazon forest’s fringes, Sudan, and southern Central Africa. Rainfall is lower and more variable, with a longer, harsher dry season and grassland vegetation.(NCERT 11)
🌟 Great to Know
Dry Climates: BS and BW
- Where They Occur Dry climates span 15° to 60° latitude on both sides of the equator. Rainfall is too low here to support normal plant growth.(NCERT 11)
- Subtropical Steppe and Desert (BSh, BWh) These sit between 15° and 35° latitude. Steppe gets slightly more rain than desert, enough for sparse grassland, but both have highly variable rainfall.(NCERT 11)
- Mid-Latitude Steppe and Desert (BSk, BWk) These sit between 35° and 60° latitude, mainly in continental interiors that maritime winds cannot reach.(NCERT 11)
- Extreme Heat Record The highest recorded shade temperature was 58°C, at Al Aziziyah, Libya, on 13 September 1922.(NCERT 11)
Warm Temperate Climates: Cwa, Cs, Cfa, Cfb
- Group C Basics These climates span 30° to 50° latitude, on the eastern and western edges of continents. Summers are warm and winters stay mild.(NCERT 11)
- Cwa – Humid Subtropical, Dry Winter Found in the North Indian Plains and interior South China. It resembles Aw climate, except winters here stay warm instead of hot year-round.(NCERT 11)
- Cs – Mediterranean Found around the Mediterranean Sea and on west coasts near 30–40° latitude, such as Central California and Central Chile. Summers are hot and dry; winters are mild and rainy.(NCERT 11)
- Cfa – Humid Subtropical, No Dry Season Found on eastern continental margins, such as the south-eastern United States and southern Japan. Rain falls all year, with thunderstorms in summer.(NCERT 11)
- Cfb – Marine West Coast Found poleward of the Mediterranean zone, such as north-western Europe and southern Chile. Sea influence keeps temperatures moderate all year, with rain spread evenly across the seasons.(NCERT 11)
Cold and Polar Climates: D, E, and H
- Df and Dw Cold snow-forest climates occur between 40° and 70° north latitude, across Europe, Asia, and North America. Df has a humid winter; Dw, found mainly in north-eastern Asia, has a dry winter with a monsoon-like wind reversal.(NCERT 11)
- ET – Tundra Found beyond 70° latitude, named for its low mosses, lichens, and flowering plants. The subsoil stays permanently frozen as permafrost.(NCERT 11)
- EF – Ice Cap Found over interior Greenland and Antarctica. Temperatures stay below freezing even in summer, and accumulated ice eventually breaks off as icebergs.(NCERT 11)
- H – Highland Governed by elevation rather than latitude. Temperature and rainfall both change sharply over short distances, creating layered climate zones up a mountainside.(NCERT 11)
📝 Exam Point of View
Exam Point of View: Climate Codes
- Real PYQ CDS (II) 2020, General Knowledge asked which code marks the Tropical Savannah climate. The answer is Aw, the tropical wet-and-dry type, not Am or Dfc.
- Real PYQ CAPF (ACs) 2020, General Ability asked which Koeppen code fits India’s Great Northern Plains. The answer is Cwg, a warm temperate code with a dry winter, not the more obvious-looking Aw.
- Common Trap The NCERT textbook’s own exercise asks which code fits most of the Indian Peninsula: the answer is Am, tropical monsoon, not Af or Aw. Learn each region’s actual code rather than guessing from “it feels tropical.”
- The Pattern Exams love swapping one letter in a code (Am for Aw, Cwa for Cwg) to test whether you know the precise criteria behind each letter, not just the general climate description.
✅ Test Yourself
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