Horse Latitudes

The horse latitudes are subtropical high-pressure belts at about 30 degrees north and south of the equator, marked by sunny skies, calm winds and very little rainfall, and also known as subtropical ridges or highs. They form where warm air that rose at the equator, having traveled poleward and cooled, sinks back down around the 30th parallel, creating persistent high pressure that suppresses cloud formation and precipitation. Many major deserts around the world, including the Sahara, Arabian, Mojave, Sonoran, Atacama, Namib, Kalahari and Great Australian deserts, lie within these latitude bands because of the steady warm, dry, sunny conditions the belts produce.