The combination of tropical latitude, mountain ranges, topography variations and two ocean currents (
Humboldt and
El Niño) gives Peru a large diversity of climates. Peru has a tropical climate with a wet and dry season.
Amazon Basin or Low Amazon The eastern portions of Peru include the
Amazon Basin or
selva baja, a region that is larger in the north than in the south. Representing roughly 60% of Peru's national territory, this area includes the
Amazon,
Marañón,
Huallaga and
Ucayali Rivers. Almost 60% of the country's area is located within this region, () giving Peru the fourth largest area of tropical forest in the world after Brazil,
Congo and
Indonesia.
Andean mountain ranges The Andes shelter the very largest variety of climates in the country. The climate is semi-arid in the valleys and moist in higher elevations and towards the eastern flanks. Rainfall varies from per year. The monsoonal period starts in October and ends in April. The rainiest months are January through March where travel can be sometimes affected. The western slopes are arid to semi-arid and receive rainfall only between January and March. Below the mark, the temperatures vary between in the night versus in the day. Between , the temperatures vary from in the night and from during the day. At higher elevations from , the
Puna ecoregion, the temperature varies from during the night versus during the day. The northernmost regions of the Andes around
Cajamarca and
Piura regions have
Páramo climates.
Coast The Peruvian coast is a microclimatic region. The region is affected by the cold
Humboldt Current, the
El Niño Southern Oscillation,
tropical latitude, and the
Andes mountain range. The central and southern coast consists mainly of a subtropical desert climate composed of sandy or rocky shores and inland cutting valleys. Days alternate between overcast skies with occasional fog in the winter and sunny skies with occasional haze in the summer, with the only precipitation being an occasional light-to-moderate
drizzle that is known locally as
garúa. These regions are usually characterized by mildly cold lows () and also mild highs (). Temperatures rarely fall below and do not go over . An exception is the southern coast, where it does get a bit warmer and drier for most of the year during daytime, and where it can also get much colder during winter nights (). The northern coast, on the contrary, has a curious tropical-dry climate, generally referred to as
tropical savanna. This region is a lot warmer and can be unbearable during summer months, where rainfall is also present. The region differs from the southern coast by the presence of shrubs, equatorial dry forests (
Tumbes–Piura dry forests ecoregion),
mangrove forests, tropical valleys near rivers such as the
Chira and the
Tumbes. The average temperature is .
Central and southern coast The central and southern coast have a
subtropical desert climate, despite this region being located in the tropics. The
Humboldt Current, serving as one cause of climatic differentiation, is colder than normal tropical seas at , thus preventing high tropical temperatures from appearing. Additionally, due to the height of the Andes cordillera, there is no passage of hot clouds from the Amazon to the coast, the climate is cooler than that of similar tropical latitudes. This can create a great deal of humidity and fog during winter months. Moreover, the Andes mountains are very close to the coast, a geographic factor that prevents
cumulus or
cumulonimbus clouds from appearing. Therefore, a shade effect is created, causing very low annual rainfall in this region. Rainfall averages per year near the Chilean border to per year on the northern coast and nearer the Andes. The central coast is composed of regions including
La Libertad,
Ancash and
Lima, which have a spring-like climate for most of the year. Foggy and sunny days intermingle around the humid sand dunes during most of the year. Most summers (February–April) have pleasant temperatures ranging from during the night to about during the daytime. Winters (August–October) are very humid, and range from during the nights to around the during the day. The spring (November–January) and autumn (May–July) months have a pleasant climate that ranges from during the day to around during the night. Moving inland into the
Yunga valleys, the climate tends to be ~ drier and warmer during any given month. The
southern coast, composed of the
Ica,
Arequipa,
Moquegua and
Tacna regions, has a drier and warmer climate during the day for all seasons, although colder in winter. There are regions famous for their sand dunes and impressive deserts that are, in part, caused by the drier and hotter climate. Temperatures in this region can reach up to in the
Nazca region while inland regions can fall to during the winter months. During the day, temperatures rarely go below the for all months of the year. This purports the idea that the southern coast has a more desert-like climate, although daily temperature variations exist as they do in other regions within tropical latitudes. Clear skies are often present in desert areas and, although less common, near the coastal cliffs as well, which are home to a variety of fish and marine mammals.
Northern coast The northern coast consists of the eastern region of
Lambayeque, the
Piura Region and the
Tumbes Region. They are characterized by having different climate and geography from the rest of the coast. Right between the 3-hour drive on the
Sechura Desert, which is located north of the
Lambayeque Region and south of the
Piura Region, is the evidence of
climate change from the common subtropical desert found on the south to visible tropicalization effects of the tropical dry climate or
tropical savanna. Examples of this are the tropical dry forests that begin to appear. They are composed of shrubs, thorny trees, carob trees, faique trees, guayacan trees, hualtaco trees, palo santo trees, ceibo trees and on the coast mangrove forests. It is also a biodiverse area where typical wildlife can be observed such as crocodiles, reptiles, iguanas, boas, pava aliblanca, anteater, bear, sloth (bearh) and many more. This climatic change is caused by the presence of the warm
El Niño Current during the summer months (December to April), the eventual
El Niño Phenomenon and the passing of Amazon Jungles clouds due to mountain openings and lower altitudes of the
Andes Chain. These are the causes for a climate change in a short two- or three-hour trajectory that is visible between the
Lambayeque Region and the
Sechura Province, where not only geography changes but a temperature rise of or more depending on the month. It is directly off the shores of the
Sechura Region where the cold Humboldt current and warm El Niño current meet, at about 5° to 6° south of the equator. From this point, warm temperatures are most common, and there are no true winters. Average temperatures range between . Summer (December through March) is more humid and very hot, with average temperatures that vary from during the night to around during the day, although north of Lambayeque it can reach the . Winters (June–September) are cooler during the nights; around during the night, to around during the daytime. There are protected areas in
Tumbes and
Piura such as the
Coto de Caza El Angolo and the
Cerros de Amotape National Park, with
tropical dry forests that extend to the south of Ecuador. The eastern areas of
Lambayeque also have tropical dry forests, where the Chaparrí Private Conservation Area is located in Chongoyape. These forests have the particularity of connecting with the
Amazon basin through the
Marañón pass (an area where there are also tropical dry forests).
Mangrove forests are located in four specific areas from
Sechura to
Tumbes. In these regions, the mangrove forests are at the ending strips of the Piura River in the
Sechura Province (the southernmost mangroves in the Pacific Ocean). To the north, the ending strips of the
Chira River,
Tumbes River, and
Zarumilla River also have mangrove forests that flow into the ocean.
Terrain: western
coastal plain (costa), high and rugged Andes in center (
sierra), eastern lowland jungle of Amazon Basin (selva).
Natural resources: copper,
silver,
gold,
petroleum,
timber,
fish,
iron ore,
coal,
phosphate,
potash,
hydropower. == Extreme points ==