The entire length of the Andes Mountain range is classified in the Köppen Climate Classification System as a highland climate (H). Also called a "mountain climate," highland climates are found in alpine biomes, typically high plateaus and mountain ranges, and feature cool temperatures that get colder as climbers reach higher altitudes. Areas considered highland climates include places such as the American Rocky Mountains and European Alps. They see less than a foot of annual rainfall and temperatures ranging from -2° F to 50° F.
Areas surrounding the base of the Andes Mountains considered dry climates (B) include Boliva and Argentina. These regions are further classified as dry tropical climate (Bw) areas, which are found in low desert biomes between latitudes 18° to 28° in both hemispheres and are characterized by low precipitation levels, less than an inch each year, light winds, and big differences in daily temperature ranges. A dry heat is perhaps the best way to describe typical weather in the Bolivian climate region of the Andes Mountains, and comparable areas classified as desert climates include the southwestern United States and the North African region.
The humid middle latitude climate (C) zone of Chile, South America's long, narrow country in the southwest, is divided into two biome classifications as it covers so much distance, resulting in sometimes vast differences in terrain and bodies of water. All humid middle latitude regions, also known as temperate regions, are characterized by dry, hot summers and damp, cold winters. Northern Chile is further categorized as a Mediterranean climate (Csb) subgroup and is characterized by extremely dry summers, and summer wildfires are an annual concern. The southern coast of Chile surrounding the Andes Mountain base is considered a moist continental climate (Cfb) subgroup, as it experiences vast seasonal changes between summer and winter, as well as a virtually nonexistent dry season.
In Columbia, Ecuador, and Peru, the areas surrounding the base of the Andes Mountains are considered tropical moist climates (A). These climate regions extend north and south of the equator to about 15° to 25° latitude and are characterized by their year-round high temperatures and precipitation levels. The base areas of the Andes Mountains in Columbia are further classified as a tropical wet climate (Af), and are characterized by almost daily rains and minimal temperature variations. These regions are the home of the famed "cloud forests" of the Andes Mountains, where high surface heat and humidity meets cold mountain air to create cumulonimbus and cumulus clouds in the early afternoon each day. In Ecuador and Peru, the base of the Andes is further classified as wet-dry tropical climates (Aw) or simply savanna climate and features dry winters and light to moderate rains during the summer.
