Climate zones

In a rainforest at the equator it is hot and humid all year, in the desert the sun beats down on dry sand, and at the poles there is eternal ice. These large areas with similar weather over many years are called climate zones. They wrap around the Earth like broad belts.

Why the sun is the boss

The most important reason for the climate zones is the sun. At the equator its light hits the Earth almost straight down and heats a small spot strongly. Near the poles the same light comes in at a very slanted angle and spreads over a much larger area, so it stays cool there. This is how ever colder zones form from the middle of the Earth towards the poles.

The great belts of the Earth

Roughly four zones can be told apart. Around the equator lie the tropics, warm and often rich in rain. Next come the subtropics: dry air sinks back down there, which is why this belt holds the great deserts such as the Sahara. Further out follows the temperate zone with its four seasons, where Germany also lies. Right at the outside, at the poles, is the cold zone with long, icy winters.

Not only the sun matters

Besides the sun, other things also play a part. High mountains are colder at the top than in the valley, even if they stand in the tropics. Being close to the sea makes the climate milder and more humid, while far inland it becomes hotter in summer and colder in winter. This is why there can still be many smaller differences within one zone.