Peru’s weather has two main seasons – dry and wet – though the climate can vary tremendously depending on the geographic region you visit. the main influence on temparature is elevation: the higher in the Andes you are, the cooler it will be.
For travel and tourism the high season is from June to August,which coincides with summer vacation in North America and Europe and the cooler dry season in the Andean highlands. If you plan to trek the Inca Trail or other route in the Cuzco area this is the best (and busiest) time to go on Peru trekking tours to Machu Picchu, or climbing, hiking and mountain biking elsewhere in Peru.
It is possible to go on Machu Picchu tours, Cuzco Peru tours and visit the highlands year-round, , though the wettest months of December to March make it a wet and muddy destination with lots of rain. The most important local festivals, such as La Virgen de la Candelaria, Carnaval and Semana Santa, occur during the wettest months and are very lively even during heavy rainstorms.
On the dry coastline, Peruvians crowd the beaches during the most warm and humid time of the year, from late December through March. In central and southern Peru, the coast is cloaked in mist (garúa) for the rest of the year. Although the southern beaches are completely deserted at this time of the year, the cities by the coast can be visited at any season. In northern Peru, beaches enjoy a lot more sun, so san loving tourists can enjoy the north coast year-round.
In the Amazon basin and eastern rainforest lowlands, obviously, it rains and rains a lot. The wettest months are December through May (best time for taking an Amazon cruise out of Iquitos, also great time for primate spotting and birdwatching), but even in the wettest months it rarely rains for more than a few hours at a time, so you can still enjoy plenty of sunshine, you can access smaller tributaries and remote areas by canoe.
Friendly advice: briefly take cover during the heaviest downpours or carry a rain poncho. The dry season in the Amazon is the best moment for lodge based wildlife touring since animals can be spotted by the dry river banks and the trails are more accessible and not completely flooded.