The Atacama Desert in northern Chile is widely regarded as the driest non-polar desert on Earth.
The Atacama lies between the Pacific Ocean and the Andes, mainly in Chile’s Norte Grande region, with extensions toward Peru, Bolivia, and Argentina. Some weather stations in its central zone have recorded no measurable rainfall for many years, while average annual rainfall in the driest areas can be less than 1 millimetre.
Its dryness results from several factors working together. The cold Humboldt Current limits evaporation and cloud formation, the Andes block moist air from the east, and a persistent subtropical high-pressure system suppresses rainfall.
Despite its harsh conditions, the Atacama is not lifeless. Fog supports specialised organisms near the coast, and hardy plants and microbes survive in isolated habitats. Its exceptionally clear skies also make it a premier astronomy location, including the site of the Very Large Telescope’s Paranal Observatory.