Climate in Lima

Although relative humidity levels are high, rainfall is very low due to strong atmospheric stability. The severely low rainfall impacts on water supply in the city, which originates from wells and from rivers that flow from the Andes.  Inland districts receive anywhere between 1 to 6 cm (2.4 in) of rainfall per year, which accumulates mainly during the winter months. Coastal districts receive only 1 to 3 cm (1.2 in). As previously mentioned, winter precipitation occurs in the form of persistent morning drizzle events. These are locally called 'garúa', 'llovizna' or 'camanchacas'. Summer rain, on the other hand, is infrequent, and occurs in the form of isolated light and brief showers. These generally occur during afternoons and evenings when leftovers from Andean storms arrive from the east. The lack of heavy rainfall arises from high atmospheric stability caused, in term, by the combination of cool waters from semi-permanent coastal upwelling and the presence of the cold Humboldt Current; and warm air aloft associated with the South Pacific anticyclone.

The climate of Lima (as that of most of the Peruvian coast) gets severely disrupted during El Niño events. Water temperatures along the coast, which usually average around 17–19 °C (63–66 °F), get much warmer (as in 1998 when the water temperature reached 26 °C (79 °F)). Air temperatures rise accordingly. Such was the case when Lima hit its all-time record high of 34 °C (93 °F).  Cooler climate develops during La Niña years. The all-time record low in