Peru weather is renewed for its diversity and the varying climates and microclimates it experiences. Conditioned by the presence of the Andes mountain range and the cold Humboldt Current Peru weather’s diversity is so great it somehow manages to include 28 of the 32 world climates.
The coastal region enjoys a subtropical type of weather and little rain, fluctuating between cool and cold in the Andes who experience rainy summers and very dry winters, while the eastern lowlands are under the influence of an Equatorial climate. Weather in the eastern lowlands remains hot with abundant rainfall throughout the year.
The coast
Coastal weather is largely determined by the influence of the cold Humboldt Current. Running parallel the Peruvian coast the current acts as a shield that block precipitation from the coast entering the region. However, the top north and south part of the South American coastal Andes experience higher amounts of precipitation.
Although situated near the Equator, Peru’s coastal region experiences great fluctuation in temperatures, as a direct result of the impact the sea surface temperatures have over the area. Commencing in January and finishing off in March summer is the warmest period in the coastal area, and winter (July to September) the coolest. There is also a marked difference between day and night temperatures the furthest from the sea an area is located.
Northern coast
Peru’s northern coast is marred by the extremities in temperature it experiences, differences that often range from 14°C to 38°C. Summer time is hot, humid and sunny, with occasional rainfalls punctuating the prevailing fine weather of the afternoon.
Again, the Humboldt Current is of immense importance to the region pushing the climate to more arid conditions in the far north, and to considerably warmer temperatures as it nears the Equator. Bordering Ecuador, the Tumbes Region is the only place on the coast with regular seasonal precipitation.
Although summer rainfall totals rarely exceed 200 mm, conditions change rapidly when the El Nino descends over the area. As a matter of fact, El Nino’s severity is so great major floods occur during its reign over the landscape, and precipitation is often pushed to highs of 4000 mm, especially in the northernmost part of the coast. Daytime temperatures range from 28–38°C, dropping slightly during the night hovering between 20–23°C. Winter is characterized by warm yet comfortable conditions and absence of rain.
Central and southern coast
The central and southern coasts of Peru experiences temperatures than range from 8 to 35°C and rainfall so scarce it’s almost negligible. During summer warm, sunny and moist conditions prevail, with temperature lows around 18°C and highs of 30°C, although in the Ica desert area they can reach 35°C. Summer is a period of very little or none rainfall, the area receiving most of its rather insignificant precipitation during the night.
During winter the dominant overcast, cool and damp conditions keep daytime temperatures cool. The areas closest to the coast are also renewed for being permanently cover in a layer of fog. The rainy season of the areas located right by the ocean commences in late May and comes to an end by mid October. Most of the rain falls as drizzle during the very early hours of the morning and seasonal totals range between 10 and 150 mm. Temperatures range from 14–18°C at night and 22–29°C during the day. Between July and August overcast skies hover over the land for several weeks, dropping high temperatures bellow the 19°C mark.
The Andes
Peru weather is at its most diverse state at the Andes mountain range. As temperatures are generally modified by altitude, weather varies from temperate in the low-lying valleys with annual average of 18°C to frigid in the highest elevations, whose temperatures often fall bellow 0°C.
Although maximum temperatures remain steady throughout the year, during the winter season the frequent presence of clouds in the sky is not only responsible for the fluctuation of temperature lows, it also often keeps night time temperatures to similar levels as those experienced during the day. On the occasions when the Andes skyline is free of clouds, the area’s nights tend to be considerably colder.
Precipitation varies according to season and location. The rainy season starts in September and peaks between January and March, the May–August period is characterized by very dry conditions and cold nights and mornings, whereas the coastal areas experience almost exactly opposite conditions.
The southwestern Andes are the driest in the region and the eastern slopes the wettest, with 200–500 mm/year and over 1000 mm/year precipitation respectively. Some regions immediately east of the Andes precipitation is significantly more peaking at around 10000 mm/year.
The distribution and rainfall amounts are abundantly influenced by the many lakes of the area. For example, Lake Titicaca receives twice as much rainfall than the surrounding terrain thanks to the impact of the nighttime convective storms it induces. Thunderstorms are occasionally followed by lighting, ferocious and hail that wrecks havoc in the area especially during the beginning of the rainy season and over higher elevations. During the rainy season, peaks of over 5000 m frequently experience snowfall, and between May and August snow falls as low as 3800 m.
The lowlands
The eastern lowlands experience an Equatorial type of climate that remains largely hot and rainy throughout the year. Temperatures fluctuate between 18–36°C and rainfall varies between 1000 and 4000 mm per year. Between May and September cold surges that originate over Argentina can lower the area’s temperatures to about 10–15°C.
