Antofagasta has a cold desert climate (Köppen BWk) with abundant sunshine and strong maritime influence. The marked aridity and water scarcity are regulated by the Humboldt Current, addition to the high humidity and morning fog known as "Camanchaca". Furthermore, the Pacific anticyclone generates winds from the south and southwest. The average annual temperature is . The average daily low temperature in the warmest month, January, is while the average daily high temperature is . The coldest month, July, sees an average low temperature of and an average high temperature of . The highest temperature recorded is in January 1998 and the lowest recorded is in September 1978. The Atacama Desert coast is subject to a climate of extreme aridity, and therefore generates a low average annual rainfall of (1970–2000), and the Town of Antofagasta itself receives an annual average of less than of rainfall per year, earning it the record as the world's driest town. However, the sporadic occurrence of heavy rainfall, together with the geomorphologic situation of the city, make it susceptible to be affected by mud flows and landslides. Between 1916 and 1999, the city was affected by floods or landslides on seven occasions: 1925, 1930, twice in 1940, 1982, 1987 and 1991, of which the most important episodes in 1940 and 1991. Geomorphology Antofagasta is grounded on rocky ground, hard and tough. Over this layer is a dense soil with sand and medium-sized rock fragments where there are remains of abundant minerals. According to the general classification of soils, Antofagasta is founded on clay loam soils of the type I and II. The city has an irregular geomorphology by the presence of steep hills (400–500 m) that are part of Chilean Coast Range, in its eastern edge, and the Pacific Ocean to the west. The formation of the rock mass, it makes the shoreline slope is very steep (Coloso, south of Antofagasta). The coastal edge of the city has volcanic sediments, in contrast to the formation of hills of sand. Stresses in the sea a rock formation called La Portada. Among the most important mountains of the geography of the town of Antofagasta is the Cerro El Ancla (1.007 m), el Cerro Chato (485 m), Cerro Moño (4.830 m), Cerro Coloso (938 m), Cerro Bolfín (961 m), Cerro Jarón (988 m), Cerro Alcalde Poblete (979 m), Cerro Gordo (668 m), Cerro Fortuna (963 m) and Cerro Moreno