Climate of Peru

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 and sunny conditions, with occasional afternoon and nocturnal light 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.

In the central and southern coasts (south of 6°S) temperature ranges from 8 to 30 °C (46.4 to 86.0 °F) and rainfall is scarce with annual totals are 150 mm. Summer is characterized by warm, moist and sunny conditions with lows between 20 and 22 °C (68.0 and 71.6 °F) and highs are between 24 and 29 °C (75.2 and 84.2 °F). Temperatures over 29 °C (84 °F) are commonly observed less than 12 days per year except at the Ica deserts where summer highs can sometimes reach 35 °C (95 °F). Little or no rainfall occurs during the summer. Very rare rainfall events are produced by the leftovers of Andean convection and occur during the night. Summer rainfall totals are generally less than 10 mm (0.4 in).

Winter is characterized by overcast, cool and damp conditions, which keep daytime temperatures cool. Strictly by the coast and a few kilometers inland, winter is determined by an almost permanent layer of fog, which creates garua, a particular mist own to coastal Peru and Chile. In those areas located right by the ocean, the so-called 'rainy season' develops by late May and comes to an end by mid October. Precipitation occurs in the form of nocturnal-morning drizzle and seasonal totals range between 10 and 150 mm (0.4 and 5.9 in). Winter precipitation favors the development of vegetation over particular coastal mountain ranges known as "Lomas". The desert green-up peaks between July and early November.

Temperatures range from 14–18 °C (57.2–64.4 °F) at night and 19–21 °C (66.2–69.8 °F) during the day. Winter highs oscillate between 15 and 21 °C (59.0 and 69.8 °F) and the lows between 8 and 15 °C (46.4 and 59.0 °F). Several weeks of persistent overcast skies and highs below 19 °C (66.2 °F) are not uncommon between July and September.

Some representative weather station averages:

• Piura (north); 55 m (180 ft); annual mean temperature 24.4 °C (75.9 °F); annual mean precipitation 72 mm (2.8 in) Climate type BWh (hot desert).
• Lima, (central); 30 m (98 ft); annual mean temperature 19.2 °C (66.6 °F); annual 15 mm (0.6 in), Climate type BWh ("subtropical" desert, but cold Humboldt Current generates fog).
• Lomas de Lachay, Huaral Province in Lima, a unique mist-fed ecosystem.

From April to July 2009, unusually cold weather resulted in the deaths of more than 100 children under the age of five.[2] In June, there were 50,000 suffering from acute respiratory infections, and 4,851 with pneumonia. Between mid April and mid June, 61 children perished.[3] The United Nations Population Fund reported over 13,500 cases of pneumonia, and more than 60,000 cases of respiratory infections. The Adventist Development and Relief Agency (ADRA) is distributing blankets and warm clothing. Whereas pneumonia cases resulting in death of infants (who are often underclothed, if not barefoot) are the norm during winter, the 2009 winter season was unusual in that it began 12 weeks earlier than usual. More than 80 of the deaths occurred in Puno, Peru, one of the larger cities of the Altiplano lying in the central Andes. The children suffering from malnourishment are the population at greatest risk in an impoverished southern area of Peru lacking health care facilities.[2][4]

Yehude Simon, presidential Cabinet Chief, reported that 27 million S/ or US$9 million was allotted for Puno and 23,230 vaccine doses were shipped out. Oscar Ugarte, the Health Minister reported that only 234 of these vaccines were administered. Carmen Vildoso, Minister of Women's Affairs, is working at developing a program to create solar panel-heated walls in residential homes to provide heating.

In June, Percy Zaga Bustinza, Director of Puno's Social Development, reported that a new Pinaya health centre would be opening up and also a small hospital in Santa Lucia. UNICEF would like action taken so that the deaths from the predictable cold weather can be prevented. As well, preventative measures should be put in place so that the cold weather no longer results in an emergency situation.[5] School hours were modified for the children's school days so they are not out in the coldest part of the day. By the middle of June, livestock and crops had been adversely affected by the cold weather across 92,000 hectares (227,337 acres) of land. In July 2009, a state of emergency was declared by President of Peru Alan García Pérez in 11 regions of Peru: Apurímac, Arequipa, Ayacucho, Cusco, Huancavelica, Junín, Lima, Moquegua, Pasco, Puno and Tacna.[3] The cold winter weather is expected to end in September.[3]

In July 2010, the Peruvian government declared a state of emergency in 16 of Peru's 24 regions due to cold weather. The majority of the areas affected were in the south, where temperatures dropped to as low as -24C. Lima recorded its lowest temperatures in 38 years at 9C, and emergency measures were applied to several of its outlying districts. In the Amazon region, temperatures dropped to as low as 9C, the fifth recorded cold spell that year. In the south, hundreds of people - nearly half of them very young children - were reported as having died of cold-related diseases such as pneumonia, and poor rural populations living at more than 3,000m above sea level were the most affected.[6]