Physical geography
Peru is situated in the western part of South America. On the north it is bordered by Ecuador and Colombia, on the east by Brazil and Bolivia, and on the south by Chile. The entire west side of Peru is bordered by the Pacific Ocean. Peru's size is 1,285,215 sq. km (496,095 sq. miles). To compare: that is roughly France, Italy and Sweden together. Or the US-states of Texas, New York, California and Maine together.
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Geographic regions
Geographically the country is divided into three main parts:
La Costa, the long, narrow coastal region, facing the Pacific
La Sierra, the mountainous Andes region
La Selva, the rainforest region of the Amazon basin.
See the satellite photos to discover Peru's geography.
Computer-generated overview of Peru. Click
the image to see a bigger version
La Costa, the coastal area, is semi-arid to arid. It stretches the Pacific coastline from north to south. Some parts are extremely dry, and rainfall is very low in this area. However, many rivers from the Andes flow through the region towards the Pacific, thus creating fertile river valleys. The capital Lima is situated in the coastal area.
La Costa: Mangrove forest in Tumbes,
the most northern part of Peru
La Costa: Extreme contrast between desert
and fertile river-valley in Arequipa
Parallel and east of La Costa is La Sierra, the central region which is part of the Cordillera de los Andes. The Andes range is a vast mountain area covering not only Peru but also parts of Bolivia, Chile, Ecuador and Argentina, and even with sub-chains going as far as Colombia in the north and Tierra del Fuego in the entire south of the continent.
La Sierra: Andes peaks. Image © Guillaume Dargaud
Peru's Andes is divided in various cordilleras, mountain ranges. The most important range is the Cordillera Occidental which, in its way, is divided into other chains with towering mountains, like the Cordillera Blanca, the Cordillera Huayhuash and the Cordillera Raura. The other main mountain chains are the Cordillera Oriental and Cordillera Central. La Sierra covers about 30% of Peru. Several of the world's highest mountains can be found here, like the Nevado Huascaran (6768 m) and the Yerupaja (6634 m). A big part of Peru's south eastern highland region, around Lake Titicaca, consists of large plains, called puna or altiplano.
The altiplano. Image © Rien
Bouw
Due to tectonic instability, there are some active volcanoes in the southern Peruvian Andes, like El Misti (5,822 m) near the city Arequipa. Peru is situated at the point where the Pacific tectonic plate (Nazca plate) and the South American plate collide.
East of La Sierra is La Selva, the tropical rainforest region of the Amazon basin. The densely forested eastern slopes of the Andes are considered part of La Selva as well, and are called montaña or cloudforest. In the northeast the sierra goes downwards into a vast tropical plain, dominated by the big rivers Ucayali and Marañon. The Amazon river begins at the point where these two rivers flow together.
La Selva: montaña landscape in the Río Mayo valley, San Martín
Rivers and lakes
There are three drainage systems in Peru. The first one is formed by about 50 rivers flowing westwards from the Andes into the coastal plain and the Pacific. The second is formed by the rivers flowing mostly eastwards from the Andes or the montaña into the Amazon basin. The third drainage system is Lake Titicaca, the highest navigable lake in the world at 3,812 m above sea level. Lake Titicaca drains into Lake Poopó in central Bolivia through the Desaguadero river.
La Selva: Near the Río Tigre
The main source of the Amazon river is the Rio Marañon, which flows from Peru's central Andes northwards through La Sierra, and later eastwards into the Amazon basin. The river Ucayali flows from south to north through the montaña, and joins the Marañon in the north east of Peru, forming the actual Amazon river. The Urubamba river, a second important source of the Amazon, flows from Peru's southern Andes northwards through the montaña where it joins the Ucayali. The rivers Tigre and Pastaza rise in Ecuador and move in south eastern direction into the Marañon. The river Napo also rises in Ecuador and flows directly into the Amazon, in the north east of Peru. The river Madre de Dios rises in Peru's southern Andes and flows eastwards into Brazil, where it joins the Madeira and eventually the Amazon.
Climate
Peru is entirely situated in the tropics, but it has so many different climate zones, that it can vary from tropical to arctic. La Costa is arid, and very moderate, with an average of about 20°C (68°F) throughout the year. The moderate climate is caused by the Humboldt Current, a cold wind blowing from the South-Pacific. The coast receives less than 50 mm precipation each year. The reason for that is that the Andes receives practically all the rain that comes from the trade winds from the east, the Amazon basin. That turns the coast into one of the driest deserts of the world. Thanks to mist-laden clouds that come with the Humboldt Current, there is still enough moisture for some desert vegetation to survive. These misty clouds are known as garua, and are one of the reasons for the moderate coastal climate. During winter (May to October) the average temperature in Lima won't be much more than 18°C, while in summer, when the garua disappears, it will be a pleasant 25°C and sunny most of the time.
La Costa: Road construction work (due to
El Niño) in the southern coastal desert
More inland, a few hundred metres above sealevel one will rise above the garua and the weather will be sunny all year round. Most parts of La Costa have a pleasant climate in summer, especially the northern city Trujillo. This city is called La Capital de la Eterna Primavera (capital of the eternal spring), but here too, the winter temperature will be moderate because of the garua. In the most northern part of La Costa, there is no garua, and around Piura and Tumbes the climate is arid and very hot during summer and winter.
In the Andes range, La Sierra, there is a dry season from May to September. Daytime temperatures are moderate, but it can be very cold during the nights. While the season may be dry, it is still winter in that part of the world. Sometimes it may freeze at night in a city like Cuzco, at 3326 m above sealevel. Precipation is average in most of La Sierra, with about 800 mm rainfall during the year. Temperatures vary from very cold in winter (-5°C) to moderate (21°C) in summer. Apart from the rain season the weather is usually sunny.
La Selva: Tropical rainforest in Manu National Park
La Selva, the Amazon region and the montaña, is extremely wet. In some districts the annual rainfall exceeds 3,500 mm. La Selva has a lot of rain during the wet season (November to April). The climate is humid and of course extremely hot.
See Peru's actual temperature charts, updated every hour
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El Niño
Every few years, the weather in Peru is heavily influenced by El Niño, a warm current from the central Pacific. El Niño has a worldwide impact, and changes the entire climate, from Brazil to Australia, from Africa to Canada. El Niño is concentrated along the coast of Peru and Ecuador. It is the strongest climatical phenomenon on earth. El Niño appeared again in 1998 as one of the most severe ever, causing floodings over Peru's deserts and extreme draught over Australia and Asia. In the northern desert district of Piura, a lake was born as a result of the immense rainfall. This lake is now the largest lake in Peru after Lake Titicaca. It will dry out eventually, unless another El Niño strikes again, but still the lake is expected to remain for several years.
