Lomas the lomas owe their existence to the moist dense fog and mist which rolls in from the Pacific. The fog is called garúa in Peru and Camanchaca in Chile. According to the Köppen Climate Classification system, the coastal desert of Peru and the Atacama desert of Chile feature a rare desert climate, that is abbreviated "Bwn" on climate maps with the n denoting frequent fog. Temperatures are mild year round and precipitation is nearly non-existent, averaging to per year in most locations. Many years have no precipitation at all. The Atacama Desert of Chile is commonly known as the driest
Sahara Desert (ecoregion) that crosses the ecoregion is the Nile River, which originates in central Africa and empties northwards into the Mediterranean Sea. Some areas encompass vast underground aquifers resulting in oases, while other regions severely lack water reserves. The Sahara Desert features a hot desert climate (Köppen climate classification "BWh"). The Sahara Desert is one of the driest and hottest regions of the world, with a mean temperature sometimes over and the average high temperatures in summer are over for months at a time, and can even soar to . In desert rocky mountains such as the Tibesti in Libya or the