Softness and mist on the coast
Located between sea level and an altitude of 500 m, the costa, although very close to the equatorial line, has an average annual temperature of 18 °C. This is due to the proximity of the cold Humboldt current which licks almost the entire coastline, causing a permanent haze which prevents the formation of rain (less than 100 mm of annual precipitation). This cloud cover the sky of the coast from May to October until 600 m of altitude, height above which the temperature becomes more lenient and the sun more present
In the north, the beaches are sunny and with an average temperature of 25 °C. After Chiclayo, the climate becomes frankly hot. In summer (from December to March), when the foggy layer dissipates, the heat is really overwhelming. The vegetation becomes more and more dense as one approaches the border with Ecuador.
Humboldt Current and Niño Costero
Every 5 years or so, El Niño appears on the Peruvian coast, and this warm current is a real disaster for the Ballestas Islands and the Paracas reserve. It is the cold Humboldt current that maintains the ocean's richness in plankton, the basic food of seals, sea lions, penguins, dolphins and birds. El Niño, which is too warm, causes this plankton to flee: animals and birds are therefore forced to migrate in search of new food. Sometimes El Niño is just a few degrees warmer, which is very pleasant in the Pacific, although it throws the food chain off balance.
Other times, El Niño gains strength and causes flooding events that ultimately have consequences just as impactful as earthquakes. Between December 2016 and March 2017, this climatic phenomenon shocked the entire country and severely affected the entire northern coastal region: Chimbote, Trujillo, Chiclayo, Piura, Tumbes and the surrounding countryside. Strong mudslides also affected the regions near Lima. A major drought and several forest fires preceded, then the warming of the Pacific waters triggered unprecedented rainfall. The dried-up rivers around which precarious housing had been built became full of water in a few hours. The toll was heavy: more than 1 million people were affected, 231,874 were affected and 143 died. The El Niño phenomenon is recurrent. Two major episodes in 1982-83 and 1997-98 caused more victims. The challenge remains to take the necessary preventive measures such as enforcing no-build zones and establishing effective river drainage systems. Unfortunately, public corruption often gets bogged down and emergency reconstruction is carried out in the same disaster areas
Sun and cold nights in the sierra
Between 2,500 and 3,500 m of altitude, the climate is temperate, but the temperature varies a lot between day and night. This is the case for example in Arequipa or in the Sacred Valley of the Incas at a lower altitude than in Cusco. The sky is often a deep blue and clear, which thanks to the proximity of the Equator line gives a comfortable feeling of warmth. However, beware of the sun's rays. On the other hand, at night, hats and ponchos are a must, as the temperature drops significantly. There is very little heating in rural houses, and even in standard hotels, which sometimes provide electric heaters. In the countryside, people gather and sometimes sleep by the stove when the nights are too cold
The higher you go, the lower the temperature and above 4,800 m, there are no settlements except for those linked to mining (Cerro de Pasco and La Oroya). On the Altiplano, in the region of Puno, at an altitude of 4,000 m, the annual temperature is cold with an average of 3 to 8 °C and frosts in the wet season (from November to May), and 10 °C in the dry season. A drop in temperature can also be felt more cruelly at night during the period known as "las heladas" between June and July.
Beware of the rainy season in the sierra from mid-December to mid-March because it often causes landslides, the rains are episodic and strong and the roads built on the side of the mountains are crumbly, this often generates cut roads that make some areas or places inaccessible for several hours or days. In this case there is no other choice but to be patient and wait for someone to come and clear the road. Even Machu Picchu is not spared by the mudflows that are called "huaicos" here, it is not the best period for a trip.
Heat and humidity in the selva
In the high selva , the average temperature oscillates between 22 and 26 °C, decreasing with altitude. Particularly intense rainfall occurs between December and April, which also causes landslides. Surprise, Machu Picchu is almost more Amazonian than Andean, located at the border of the two geographical regions. On the archeological site the weather is often quite good, but it is also a rainy place and subject to mists that do not take anything away from its mysticism. The ruins of Kuélap in northern Peru have the same geographical characteristics. The rest of the year, from May to November, the climate is generally dry and hot. This becomes increasingly true as one leaves the Andes behind and approaches the Amazon plain.
In the lower selva , the average temperature is 31°C, but it can feel hotter because of the humidity that sticks to your skin and envelops you. The deforested cities (Iquitos, Pucallpa, Puerto Maldonado) have much higher temperatures and feel than the forest itself. At certain times of the day, no one goes out and fans are running everywhere. In the heart of the forest, the humidity is present, but the heat remains bearable. It rains less than in the high selva , but the humidity is high and thunderstorms are frequent. It is possible to visit the region during the rainy season, but we do not recommend it because the animals are absent. On the other hand, navigating in Iquitos, for example, which is partially submerged, can have its charm.
