Climate of Peru

The climate of Peru is very diverse, with a large variety of climates and microclimates, including 30 of the 32 world climates. Such a diversity is chiefly conditioned by the presence of the Andes mountains and the cold Humboldt Current

The climate on the coast is subtropical with very little rainfall. The Andes mountains observe a cool-to-cold climate with rainy summers and very dry winter. The eastern lowlands present an Equatorial climate with hot weather and rain distributed all year long.

The climate of the coast ranges from warm-semiarid (north of 10°S, and thus very close to the equator) to a climate which is a bit like the Mediterranean (Köppen Csb) climate with an important difference — the winter, although cloudy, cool and very humid, does not have sufficient rainfall to be considered a Köppen C climate.

The high coastal climate is chiefly determined by the influence of the cold Humboldt Current, which runs parallel to the Peruvian coast, blocking the possibility of precipitation coming from the Ocean. Should this current be warm instead, the presence of the Andes would suffice for high amounts of orographic precipitation, such as registered in the top north and south part of the South American coastal Andes.

The temperature extremes of the northern coast (3°S–6°S) range from 30 to 38 °C (86.0 to 100.4 °F). Summers are characterized by hot, humid and sunny conditions, with occasional afternoon and nocturnal rainshowers. The farther north, the less arid, due to the Humboldt Current getting less cold as it nears the Equator. Thus, the Tumbes Region, bordering Ecuador, is the only coastal one with regular seasonal precipitation.

Summer rainfall totals rarely exceed 210 mm (8.3 in), save for severe El Niño events, which can provoke major floodings, with precipitations which can be as high as 4,500 mm (177.2 in), especially in the readings observed over the entire Peruvian coast; the aforementioned Tumbes region and Piura are the hottest. Winter is characterized by warm yet comfortable conditions and absence of rain.

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