Weather and Climate in Lima

The climate of Lima is particularly given their situation. It combines a lack of rainfall, with a high level of atmospheric moisture and persistent cloud cover. Thus, surprisingly strange characteristics in spite of being located in a Tropical Zone 12 degrees south latitude and almost to sea level. The Peruvian central coast shows a series of atypical microclimates due to the influential and cold Humboldt Current derived from Antarctica, the proximity of the mountains and the location tropical giving Lima a subtropical, desert, humid climate at the same time.

We can say that Lima has a warm climate without excessive tropical heat or cold extremes requiring have heating at home, with the exception of very few winters. The average annual temperature is from 18.5 to 19 ° C, with an annual summer maximum of about 29 ° C. Summer, from December to April; have temperatures ranging from 28 to 21 ° C. Only when the phenomenon El Niño occurs, the temperature in summer can exceed 31 ° C. Winter range from June to mid-September with temperatures ranging from 19 to 12 ° C and 5 ° C lower temperature historically proven. The months of spring and autumn (September, October-may) have warm temperatures ranging from 23 to 17 ° C.

On the other hand, the relative humidity is very high (up to 100%), producing persistent fog from June to December until the entrance to the summer when the clouds are smaller. It is sunny, humid and hot summers (december-april), cloudy and mild in winter (June to September). Rain is almost non-existent. The annual average is 7 mm reported at the airport, being the least amount in a metropolitan area in the world. Lima has only 1284 hours of sunshine per year, 28.6 hours in July and 179,1 hours in January, exceptionally low values for latitude.

The combination of climatic phenomena occur well: the cold Humboldt Current that runs along the coast is significantly cooled water temperature. This is much cooler that would correspond to the tropical latitudes were Lima is located. Conditions of cold in the sea with a warmer upper atmosphere by solar action generated a thermal inversion that prevents the phenomenon of convection, whereby the warmer, less dense air rises. This, together with the surrounding Andes, makes present an almost permanent layer of thick extremely low clouds (to less than 500 m from the ground) that prevents the passage of direct solar radiation. In turn, blocking by a layer of upper hot air, prevents the formation of clouds of vertical development Cumulonimbus, which explains the lack of rainfall. This is the reason however, desert and the paradox of having an extremely cloudy and humid climate. Low rainfall (less than 8 mm annual) known as drizzle are product of the condensation of low cloud that forms the system.