Climate zones

World climate zones

To help explain climate zones, let’s look at some of the main ones in a bit more detail.

We divide climate zones by their latitude on the planet:

• Tropical climates are close to the equator and have high temperatures and rainfall.
• Dry climates are immediately north and south of the tropical zone.
• Temperate climates are north and south of the dry zone, although they often overlap in latitude with continental climates in North America and Asia. These continental climates are less influenced by oceans and may have wider climate extremes.
• Polar climates are only in the Arctic and Antarctic regions.

A simplified map of the world's climate zones.

Local weather patterns and the arrangement of continents also affect these zones.

For example, the UK has the same latitude as most of Canada but has a much milder climate. This difference is because of the influence of the Gulf Stream and the North Atlantic.

We also find very different climates in the western and eastern parts of continents because of the direction of prevailing winds.

Let’s take a closer look at some key climate zones — what defines them, and where we find them.

Tropical rainforest climate 

We find tropical rainforest climates in:

• South America
• Africa
• South-east Asia

Lying either side of the equator, we characterise tropical rainforest climates by high temperatures and year-round rainfall.

Average temperatures are usually around 20–30 °C, with minor variation over the year.

Rainfall is over 60 mm of rain in every month, giving rise to thick jungles and some of the highest biodiversity seen on land.

Other tropical climates

Tropical regions also contain other climate zones, which are hot but have distinct dry seasons, unlike rainforests.

Tropical monsoon climates have a season of heavy rainfall, connected to a seasonal change in wind direction.

Tropical savanna climates have a more pronounced dry season than monsoon areas. They also have grasslands, rather than jungle.

Desert climate

Descending air north and south of the tropical zone produces almost permanent areas of high pressure across the subtropics. This produces almost cloud-free skies virtually year-round, giving rise to deserts.

Desert climates are extremely dry, and their cloudless skies lead to large temperature swings. Deserts have some of the hottest temperatures on Earth, but many will drop below freezing at night.

Though normally associated with hot, sandy environments, cold deserts also occur in many countries. The Gobi Desert of East Asia is one example, where annual average temperatures can be below 0 °C.

Whether hot or cold, deserts pose great challenges for the plants and animals that live there, which must adapt to extreme, prolonged water deficits.

Temperate climate

We find temperate climates in:

• Most of Western Europe
• Western and eastern regions of USA
• Eastern China

We define temperate zones according to temperature. Their coldest month averages between 0 °C and 18 °C, but at least one month averages above 10 °C.

We subdivide temperate climates based on their maximum temperatures and whether they have a distinct dry season — either in summer or winter. Prevailing weather patterns or local topography can often influence this.

Continental climates (mostly found in Eurasia and North America) are broadly similar to temperate ones but have greater temperature extremes. This is because they are mostly in the continental interior, away from the temperature buffering effect of nearby oceans.

Mediterranean climate

A Mediterranean climate is a specific type of temperate climate, characterised by dry summers and mild, wet winters.

This climate is often connected to weather patterns and prevailing winds. As a result, we typically find areas with a Mediterranean climate on the western coasts of continents.

Mediterranean climates take their name from the Mediterranean Basin, but we can also find them on other continents. Much of California has a Mediterranean climate, as do parts of Western Australia, Chile and South Africa.

Mediterranean climates often bring particular types of vegetation, such as the maquis in the Mediterranean, the chaparral in California and the fynbos in South Africa.

Polar climate

Prolonged cold defines a polar climate, with no months of the year averaging above 10 °C.

The ice cap climate dominates the Arctic and Antarctic regions. Here, no months average above 0 °C. Plants cannot grow, and snow and ice gradually accumulate until they slide or flow elsewhere as glaciers.

Ice cap climates can also occur at great altitude, such as the highest Himalayan peaks.

Tundra climate

If the warmest month in an area averages between 0 °C and 10 °C, we classify it as a tundra.

In tundra climates, some plant life can grow, but the growing season is too short for trees. Instead, you’ll find dwarf shrubs, grasses, and other small plants.

Animals in tundra climates have adapted to the cold and include reindeer, musk ox, and Arctic hare.

Like polar climates, tundra climates can occur at altitude. When this happens, we usually call it an Alpine climate. The summits of Ben Nevis and Cairn Gorm are in the tundra climate zone. Northern Canada and Eurasia contain some of the largest areas of tundra, and it also occurs on various sub-Antarctic islands.

Climate zone map

Map showing the current distribution of Köppen climate zones around the world. (Source:  Beck et al. (2018))

The map shows:

• Tropical climates (A)
• Dry climates (B)
• Temperate climates (C) 
• Continental climates (D)
• Polar climates (E)

You can see that tropical climates are close to the equator, occurring in central Africa, central America, and parts of Asia.

We have dry climates in northern and southern Africa, most of Australia, parts of Asia and the western tips of the Americas.

Temperate climates spread across the continents. Most of western Europe has a temperate climate, but you also find it in eastern North America, parts of Argentina and south-eastern Brazil, and even the eastern tip of Australia.

Continental climates are mostly in the continental interiors of Canada and Russia, with some in the northern USA.

Finally, polar climates are in the most northern reaches of Canada and Russia, Greenland, and, of course, the Arctic and Antarctic.

Will climate change affect climate zones?

Yes, the distribution of climate zones will change as the climate warms. You can find more information about these changes, and the precise classification of the climate zones, in a paper by Beck et al. (2018).