With the climate controls in mind, geographers sort the world's climates into a few big groups. The system most use was first worked out by the climate scientist Wladimir Köppen in 1884 and improved over many years.
Key idea
The five main climate groups are tropical (A), dry (B), temperate (C), continental (D) and polar (E). Many maps add highland climates for high mountains, where the climate changes with height.
| Group | What it is like | Where |
|---|---|---|
| A Tropical | Warm every month (all above 18 °C) | Near the equator: Amazon, Congo, Southeast Asia |
| B Dry | Less rain than the heat evaporates | Near 30° N and S, and deep inside continents |
| C Temperate | Mild winters, warm or hot summers | Mid-latitudes, often near coasts: southeastern U.S., western Europe |
| D Continental | Cold, snowy winters; warm summers | Inside large northern continents: Canada, Russia |
| E Polar | Cold all year; even the warmest month below 10 °C | Arctic coasts, Greenland, Antarctica |
Why it works
Each group comes from a mix of the controls. Tropical climates sit where the Sun is high all year. Dry climates form where air sinks (near 30°), behind mountains, or far from the sea. Temperate and continental climates are both in the middle latitudes; the ocean is what makes the difference: coasts get mild winters, inland areas cold ones. Group D is found almost only in the Northern Hemisphere, because the Southern Hemisphere has no large land areas at those latitudes.
Worked example: Which group?
A place has a coldest month of −15 °C and a warmest month of 20 °C, with rain or snow in every season. Which group?
- The warmest month is above 10 °C, so it is not polar.
- The coldest month is well below 0 °C, so it is not temperate.
- It is wet enough not to be dry.
Answer: Continental (D).
Common mistake
Thinking climate zones are neat bands by latitude. The bands are bent: deserts sit near 30° N and S, west coasts in the middle latitudes are milder than east coasts, and mountains have their own climates. Spain and the Sahara are close together but have different climates. Try it in the Climate Zones lab, linked on this page.