Why do deserts form?

Deserts form in regions where evaporation exceeds precipitation, leading to extremely dry conditions. Many deserts, like the Sahara, are located near 30° latitude due to atmospheric circulation patterns that create high-pressure zones. Others, such as the Atacama, are in the rain shadow of mountains, where moist air loses its water content before reaching the desert. Coastal deserts form due to cold ocean currents, which reduce humidity and rainfall. These factors combine to create some of the planet’s most arid landscapes.