Climate types and biomes are related but they are not the same thing. A climate type is defined by temperature and rainfall figures; a biome is the living community that grows there. Usually one predicts the other — and the interesting part of this page is the times when it does not.
📘 What you need to know
Three general climate types: tropical, temperate and polar.
Tropical splits into seasonal (wet and dry seasons, savanna) and equatorial (wet all year, rainforest).
Temperate splits into maritime (coastal, mild and wet) and continental (inland, greater extremes).
Polar climates are very cold, dry and often windy, supporting tundra.
Climate types and biomes are not the same thing — you need to know how they correlate.
The predicted biome may not develop because of secondary influences or human intervention.
The three broad zones
The dry belts sit between tropical and temperate, which is exactly where the Hadley cell brings sinking air down. Climate zones and circulation cells line up because one causes the other.
Tropical climates
Found close to the equator, between the Tropics of Cancer and Capricorn. High temperatures and high rainfall, with most regions having two seasons rather than four.
Seasonal tropical
Distinct wet and dry seasons.
Rainfall is abundant in the wet season, averaging over 1000 mm per year.
Supports savanna — grassland scattered with trees.
Examples: forests of the Congo, tropical forests of Panama and Nicaragua, seasonal forests of the Indian subcontinent, Indochina and northern Queensland.
Equatorial tropical
High temperature and high humidity all year round.
Consistent rainfall: over 60 mm in every month, and over 2000 mm annually.
Supports tropical rainforest — dense vegetation, very high biodiversity.
Examples: Amazon rainforest, Southeast Asian rainforest.
The quickest way to tell these two apart in a data question is the dry season. If every month has decent rainfall, it is equatorial and you should expect rainforest. If there is a clear dry spell, it is seasonal and you should expect savanna.
Temperate climates
Moderate mean annual temperatures — above 10 degrees C in the warmest months and above about minus 3 degrees C in the coldest. Most regions have four seasons.
Feature
Maritime temperate
Continental temperate
Position
Coastal, often the western side of continents
Interior of continents, away from ocean influence
Temperature
Mild wet winters, cool dry summers; smaller annual range
Hot summers and cold winters; greater extremes
Rainfall
Consistent through the year
Lower and less reliable
Why
Oceans store heat and moderate nearby land; prevailing winds bring moist air
No large water body to buffer temperature
Biome
Temperate forest with diverse tree species
Grassland or deciduous forest
Examples
UK, Ireland, coastal France, Spain and Portugal; Pacific Northwest of North America
Interior Eurasia, mainly Russia; interior North America
The main biomes in temperate climates are temperate forests, grasslands and scrublands.
Polar climates
Very low temperatures — average below 10 degrees C in every month, and below 0 in all months in the Arctic and Antarctic.
Limited precipitation, mostly falling as snow.
Often windy.
Examples: Arctic and Antarctic regions, northern Canada, Russia, Greenland.
These climates support tundra, with a short growing season and vegetation limited to mosses, lichens and low shrubs. Ice caps and glaciers cover much of the area, and very few organisms survive there.
When the predicted biome does not appear
This is the part that separates a good HL answer from an average one. Temperature and rainfall predict a biome, but two groups of factors can override that prediction.
Secondary influences
Soil quality — poor soil limits plant growth even where the climate is suitable.
Topography — mountains, valleys and slopes alter drainage, sunlight exposure and temperature.
Fire and natural disturbance — frequent fires or storms change which vegetation can establish.
Human intervention
Land that would naturally become temperate forest is instead a city or farmland.
Agriculture changes the natural vegetation and alters soil quality.
Urban development creates the urban heat island effect, raising local temperatures and changing rainfall patterns.
How to use this in an essay. Predict the biome from the climate data first, then add a sentence acknowledging that soil, topography, fire or human land use may prevent it developing. That structure — prediction then qualification — reads as genuine understanding rather than recall.
WORKED EXAMPLE
A location has monthly rainfall above 60 mm every month, annual rainfall of 2600 mm, and temperatures between 25 and 29 degrees C all year. Classify the climate type and name the expected biome.
Step 1: Check the temperature rangeconsistently 25 to 29 – high and stable, so tropicalStep 2: Check for a dry seasonEvery month is above 60 mm, so there is no dry seasonStep 3: Match the subtypeno dry season plus over 2000 mm = equatorial tropicalEquatorial tropical climate, tropical rainforest biome
WORKED EXAMPLE
Climate data for a region predicts temperate deciduous forest, but a survey finds mostly grassland and cropland. Suggest two reasons.
Step 1: Consider secondary influencesThin or poor soil, or frequent fire, can stop trees establishingStep 2: Consider human interventionforest cleared for agricultureStep 3: Give the reasoningBoth prevent the climate-predicted community from developingPoor soil or fire, plus clearance for farmingName the mechanism, not just the factor
💡 Exam tip
Keep climate type and biome separate in your wording. Say “an equatorial climate, which supports tropical rainforest”.
Use the dry season test to split seasonal from equatorial tropical climates.
Use annual temperature range to split maritime from continental temperate climates.
Quote a figure where you have one — over 2000 mm, below 250 mm, above 10 degrees C.
Always add a line about secondary influences or human intervention when asked why a biome is absent.
⚠ Common mix-up
Treating climate type and biome as the same word. One is the physical conditions, the other is the living community.
Assuming tropical always means rainforest. Seasonal tropical climates give savanna.
Thinking maritime climates are warmer overall. They are milder — a smaller range, not a higher average.
Forgetting the dry belts. Between tropical and temperate sit the desert zones created by the Hadley cell.
Ignoring human land use. Across much of the world the natural biome was removed centuries ago.
Up next: El Niño and the Southern Oscillation (HL) — what happens when the Pacific trade winds weaken, and why it matters worldwide.
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