What is a desert?

Deserts are arid ecosystems that receive fewer than 25 centimeters (10 inches) of precipitation a year.

Deserts are areas that receive very little precipitation. People often use the adjectives “hot,” “dry,” and “empty” to describe deserts, but these words do not tell the whole story. Although some deserts are very hot, with daytime temperatures as high as 54°C (130°F), other deserts have cold winters or are cold year-round. And most deserts, far from being empty and lifeless, are home to a variety of plants, animals, and other organisms. People have adapted to life in the desert for thousands of years.

Deserts are found on every continent and cover about one-fifth of Earth’s land area. They are home to around 1 billion people—one-sixth of the Earth’s population.