World Climate Types & Climatic Regions – NDA Geography Notes

Introduction

Weather is what happens in the atmosphere on a given day. Climate is the average pattern of weather in a region over many years — typically 30 years or more. While weather is unpredictable, climate is remarkably consistent and predictable. The tropical rainforest is always hot and wet. The Sahara is always hot and dry. The Arctic is always bitterly cold. These are not accidents — they are the result of latitude, pressure belts, wind patterns, ocean currents, and continental position working together.

This chapter organises the world’s enormous variety of climates into a manageable framework. The classification used here is based broadly on Koppen’s climate classification — the most widely used system in geography.

NDA tests this chapter through climate type identification from given characteristics, matching climate types with regions or cities, and specific questions about Mediterranean climate, monsoon climate, and tundra. Understanding the logic of why each climate type exists where it does — rather than just memorising names — is the key to answering unfamiliar questions.

Understand the Topic

The Basis of Climate Classification

Climate depends on several interacting factors:

Latitude — determines the amount of solar energy received. The most fundamental factor.

Altitude — higher areas are cooler. Temperature falls about 6.4°C per km of altitude.

Distance from the ocean — oceans moderate temperature. Coastal areas have smaller temperature ranges. Continental interiors have extreme temperature ranges.

Prevailing winds — determine whether a region receives moisture or dry air. Windward coasts facing moisture-bearing winds receive heavy rainfall. Leeward sides are dry.

Ocean currents — warm currents raise coastal temperatures and increase moisture. Cold currents cool coasts and suppress rainfall.

Topography — mountains create rain shadows and orographic rainfall patterns.

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Major Climate Types

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1. Equatorial Climate (Tropical Rainforest Climate)

Location: Within about 5°–10° of the equator — the Amazon Basin (South America), Congo Basin (Africa), and the islands of Southeast Asia.

Temperature: High throughout the year — average around 26–28°C. No real seasons — every month is hot.

Rainfall: Heavy throughout the year — annual rainfall typically exceeds 2,000 mm. Convectional rainfall almost every afternoon.

Key characteristics:

• No dry season
• Highest biodiversity on Earth
• Dense tropical rainforest (selvas)
• High humidity throughout the year
• Very small annual temperature range

The equatorial regions experience more than one period of rainfall maximum in a year. [NDA tested via CDS]

The double rainfall maxima — the highest rainfall occurs around the equinoxes (March and September) when the ITCZ passes overhead twice as it migrates north and south. [NDA tested via CDS]

2. Tropical Monsoon Climate

Location: South Asia (India, Bangladesh, Myanmar), Southeast Asia, West Africa.

Temperature: Hot throughout the year — but with a very hot dry season and a cooler wet season.

Rainfall: Strongly seasonal — most rainfall in 3–4 months of the monsoon season; dry for the rest of the year. Total annual rainfall can be very high (Cherrapunji, India receives over 11,000 mm per year).

Key characteristics:

• Strongly seasonal rainfall
• Distinct wet and dry seasons
• High temperatures throughout the year

The monsoon is driven by seasonal reversal of winds — the southwest monsoon brings rain to South Asia from June to September. [NDA tested via CDS]

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3. Tropical Savanna Climate

Location: Between the equatorial zone and the tropical deserts — approximately 5°–20° latitude in Africa, South America, and northern Australia.

Temperature: Hot throughout the year.

Rainfall: Seasonal — there is a distinct wet season (when the ITCZ moves over the region) and a distinct dry season (when the subtropical high pressure belt dominates). Annual rainfall typically 600–1,500 mm.

Key characteristics:

• Hot with alternating wet and dry seasons
• Tall grasses with scattered trees (acacia in Africa)
• Fires common in dry season

The savanna climate is between the equatorial zone and the hot deserts. When it is summer in the Northern Hemisphere, the ITCZ moves north — bringing rain to the northern savanna. When it moves south in winter, the dry subtropical high pressure takes over. [NDA tested via CDS]

4. Hot Desert Climate

Location: Subtropical high pressure belts — approximately 20°–30° latitude. The Sahara, Arabian Desert, Thar Desert, Australian Desert, Atacama, and Kalahari.

Temperature: Very high in summer — exceeding 50°C in some places. Cold at night and in winter — because the lack of cloud cover allows rapid heat loss.

Rainfall: Extremely low — less than 250 mm per year. Some areas receive virtually no rainfall for years at a time.

Key characteristics:

• Highest maximum temperatures on Earth
• Greatest daily temperature range (hot day, cold night)
• Almost no clouds
• Very low humidity
• Very sparse vegetation (xerophytes)

Hot deserts are in the subtropical high pressure belt because sinking air suppresses cloud formation and rainfall. [NDA tested via CDS]

The world’s driest place is the Atacama Desert in Chile — some parts have not received any rain in recorded history. [NDA tested via CDS]

The highest temperature on Earth was recorded in the Sahara Desert (Al-Aziziyah, Libya — or in some records, Death Valley, California). [NDA tested via CDS]

5. Mediterranean Climate

Location: Found on the western sides of continents between approximately 30° and 45° latitude — the Mediterranean basin, California, central Chile, southwestern Australia, and Cape of Good Hope (South Africa). [NDA 2010-II | NDA tested via CDS]

Temperature: Hot, dry summers. Mild, wet winters.

Rainfall: Rainfall comes in winter — when the westerlies and associated frontal systems move equatorward. Summers are dry — because the subtropical high pressure belt moves poleward in summer, suppressing rainfall.

Annual rainfall: 300–900 mm — most falling between October and March (in the Northern Hemisphere).

Key characteristics:

• Hot dry summer + mild wet winter
• Vegetation = sclerophyll (hard, waxy leaves adapted to drought)
• Named after the Mediterranean Sea region
• The only climate type with winter rainfall in the subtropics

Examples:

• Mediterranean basin = Rome, Athens, Barcelona
• California = Los Angeles, San Francisco (the California Current offshore is cold — moderates temperature)
• Central Chile = Santiago
• South Africa = Cape Town
• Southwestern Australia = Perth

[NDA 2006-I | NDA 2010-II | NDA tested via CDS]

Why Mediterranean climate receives winter rain:

In summer, the subtropical high pressure belt sits over the Mediterranean region — suppressing rainfall. In winter, this high moves equatorward and the westerlies and frontal systems move into the region — bringing rainfall. So Mediterranean climates have summer drought and winter rain — the reverse of most tropical climates. [NDA tested via CDS]

Mediterranean agriculture:
Mediterranean regions are famous for grapes, olives, citrus fruits, and wine — all adapted to the hot dry summer and mild wet winter. [NDA tested via CDS]

6. Steppe Climate (Semi-Arid Climate)

Location: Continental interiors in mid-latitudes — the steppes of Central Asia and Russia, the Great Plains of North America.

Temperature: Large annual range — hot summers, cold winters.

Rainfall: Low — 250–500 mm per year. Too dry for forests but enough for grasses.

Key characteristics:

• Temperate grasslands
• Very large temperature range between seasons
• Insufficient moisture for trees
• Fertile soils (chernozem)

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7. Humid Continental Climate

Location: Northern USA, southern Canada, much of Eastern Europe and northeastern China.

Temperature: Very large range — hot summers, cold winters. No month is completely frost-free.

Rainfall: Moderate — 500–1,000 mm — distributed throughout the year, with some summer maximum.

Key characteristics:

• Four distinct seasons
• Cold, snowy winters
• Hot summers
• Mixed forest and grassland
• Some snowfall in winter months

8. Temperate Oceanic Climate (Maritime West Coast Climate)

Location: Western coasts of continents between about 40°–60° latitude — Western Europe (UK, France, Germany, Netherlands, Scandinavia), Pacific coast of North America (Oregon, Washington, British Columbia), southern Chile.

Temperature: Moderate — neither very hot in summer nor very cold in winter. The ocean provides a moderating influence throughout the year.

Rainfall: Moderate to heavy — distributed throughout the year. Particularly in winter when frontal systems from the Atlantic are frequent.

Key characteristics:

• Mild, wet climate
• No extreme temperatures
• Year-round rainfall but with a slight winter maximum
• Deciduous forests

Western Europe has a mild, wet climate because of the North Atlantic Drift (extension of the Gulf Stream) which warms the western coasts. [NDA 2010-I | NDA tested via CDS]

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9. Temperate Continental Climate

Location: Deep continental interiors of North America (prairies) and Asia (steppes).

Temperature: Extreme — very hot summers, very cold winters. The largest temperature ranges of any climate type.

Rainfall: Low — 250–500 mm — mainly in summer.

Key characteristics:

• Extreme temperature range
• Short hot summer; very long, bitterly cold winter
• Grasslands and prairies

The verkhoyansk area of Siberia, Russia — sometimes called the pole of cold — experiences extreme continental climate with temperatures below −70°C in winter and above 30°C in summer. This is the greatest temperature range of any inhabited place on Earth. [NDA tested via CDS]

10. Mediterranean vs Monsoon Climate — Key Distinction

NDA has directly tested the difference between Mediterranean and monsoon climates.

Feature	Mediterranean	Monsoon
Rain season	Winter	Summer
Dry season	Summer	Winter
Location	West coast, 30°–45°	South/Southeast Asia, West Africa
Cause of rain	Westerlies + frontal	ITCZ migration + sea-land pressure diff
Vegetation	Sclerophyll shrubs	Tropical deciduous/monsoon forest

The Mediterranean climate has winter rainfall and summer drought. The monsoon climate has summer rainfall and winter drought. [NDA tested via CDS]

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11. Taiga Climate (Sub-Arctic Climate)

Location: Large band across Canada, Alaska, Russia, and Scandinavia — roughly 50°–70°N.

Temperature: Short, cool summers. Extremely cold, long winters. Second coldest climate type after tundra.

Rainfall: Very low — 200–500 mm — mostly as snow.

Key characteristics:

• Dominated by coniferous forest (taiga/boreal)
• Very short growing season (less than 4 months)
• Permafrost in some areas
• Long winter darkness

12. Tundra Climate

Location: Above the Arctic Circle — northern Canada, Alaska, Siberia, and Greenland. Also found at high altitude in mountains (alpine tundra).

Temperature: Always cold. Average temperature of the warmest month is below 10°C.

Rainfall: Very low — less than 250 mm — mostly as snow.

Key characteristics:

• No trees (permafrost prevents root growth)
• Vegetation = mosses, lichens, sedges, dwarf willows
• Very short growing season (less than 2 months)
• Permafrost

The absence of trees in the tundra is due to permafrost — permanently frozen subsoil that prevents tree roots from penetrating. [NDA 2011-I]

The tundra climate has the coldest average temperatures of any land-based climate. [NDA tested via CDS]

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13. Ice Cap Climate

Location: Greenland and Antarctica — the polar ice caps.

Temperature: Always below freezing. Average monthly temperatures never rise above 0°C.

Rainfall: Virtually zero — any precipitation is as snow but is very little.

Key characteristics:

• Permanent ice cover
• No vegetation
• World’s lowest recorded temperatures

The lowest temperature on Earth was recorded at Vostok Station, Antarctica at −89.2°C. [NDA tested via CDS]

Koppen’s Climate Classification

The most widely used climate classification system was devised by Wladimir Koppen — a German-Russian climatologist. He classified climates based primarily on temperature and precipitation patterns and related them to vegetation. [NDA tested via CDS]

Koppen’s five main groups:

• A = Tropical climates (no cold season; all months above 18°C)
• B = Dry climates (evaporation exceeds precipitation)
• C = Temperate climates (mild winters; coldest month between 0°C and 18°C)
• D = Continental climates (cold winters; coldest month below 0°C)
• E = Polar climates (no warm season; warmest month below 10°C)

[NDA tested via CDS]

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Mediterranean Climate — Special Focus

Because NDA tests Mediterranean climate repeatedly, it deserves extra attention.

The four defining characteristics of Mediterranean climate:

1. Hot, dry summer
2. Mild, wet winter
3. Located on western coasts of continents between 30°–45° latitude
4. Annual rainfall 300–900 mm with winter maximum

City examples that have Mediterranean climate:

• Rome, Athens, Lisbon, Barcelona (Mediterranean basin)
• Los Angeles, San Francisco (California, USA)
• Santiago (central Chile)
• Cape Town (South Africa)
• Perth, Adelaide (southwestern Australia)

[NDA 2006-I | NDA 2010-II | NDA tested via CDS]