Due to the combined factors of its location just south of the equator, the distribution of the Andes Mountains and the predominantly cold ocean current off its coast, Peru has one of the most varied climates and landscapes in the world.
Peru is normally divided into three extensive geographical regions: The Costa (coast) is desert, a flat or undulating territory between the Pacific Ocean and the Andes. The Sierra (highlands) is the mountanious territory corresponding to the Andean range. The Selva (tropical forest) is the flat, wooded and rainy región on the eastern side of the Andes range.
However, ancient Peruvians divided this territory into eight natural regions. Each one of these regions covers the territory from north to south and alternately from the west to east, running along the Andean range. These regions are:
Costa or Chala: covering the territory between the sea and 1,640 feet on the western slopes of the Andes. Here the climate is temperate (due to the moderating influence of the ocean), with occasional light rains and desert landscapes with valleys irrigated by rivers that descend from the Andes.
The cities of Piura, Chiclayo, Trujillo, Lima, Ica and Tacana are all located within this región.
Yunga: the Coastal Yunga rises from 1,640 to 7,540 feet on the western slopes of the Andes. It is a rugged, desert landscape and receives occasional light rains. The Fluvial Yunga is found between 7,540 and 3,280 feet on the Eastern face of the Andes, and its climate is cooler and wetter and the vegetation is denser than that of the Coastal Yunga.
Quechua: this región rises from 7,540 to 11,480 feet. It is characterized by a temperate, dry climate, with an average temperatura that ranges from 52 to 62 °F, with a considerable diurnal range. It receives anual rains from December to March and drought the rest of the year. It is the most populated región of the Sierra and the ancentral home of Andean culture.
The inter-Andean valleys and the most important cities of the Andes are found in this región (Cajamarca, Huaraz, Huancayo, Cusco, Arequipa Ayacucho). The Sierra, together with part of the Costa and the Selva, consumes food from this región.
Suni or Jalca: this región rises from 11,480 to 13,120 feet. Its climate is cold and the topography is undulating. This is the highest altitude at which agricultura can be practiced.
Puna: this área rises from 13,120 to 15,740 feet. The climate is cold and the terrain rugged and undulating. The air is thin. Llamas, alpacas and vicuñas graze on the coarse grass known as ichu which grows in this región.
Janca or Nival: this región extends from 15,740 feet to the highest mountain peaks of the Andes. It is glacial and thawing in this zone gives rise to the rivers which irrigate the valleys of the Costa, Sierra and Selva.
High Jungle: this región lies between 3,280 and 1,310 feet on the Eastern side of the Andes. Its topography is rugged and the climate is hot and humid. The rainy season is from December to March. This zone is rich in vegetation. The Amazon jungle begins in this región.
Low Jungle: this covers the área between 1,310 and 260 feet to the east of the Andes. The climate is hot, humid and rainy (with up to 5,000 mm of precipitation falling annually). This zone is rich in vegetation and is the best example of tropical rainforest.