In Cusco and its environs (including Machu Picchu, the Inca Trail, and the Sacred Valley), the dry season is roughly from April to early November, and the rainy season runs roughly from late November to March. The precipitation is not generally in the form of continuous rainfall; instead, there will be some rain and then it will generally be clearer for part of the day. The Andes become much greener during this time of year. Travel takes place to Peru all year round, with the only exception that trekking tours (such as the Inca Trail to Machu Picchu) generally do not take place during the wettest months of January to March.
Machu Picchu is at 8,000 feet, and Cusco is at 11,000 feet. At night in Cusco it can drop down into 40s and lower 30s during the dry season, so you should be prepared for cold weather. Temperatures are generally a bit warmer in the wet season. During the day temperatures will typically be in the 60s and 70s. On the Inca Trail, it can drop down into the 30s or 20s at night.
Seasons in the Galapagos have become less predictable in recent years, but December to May is generally considered the hot season and June to November the cooler season. In reality, throughout the year there are very agreeable temperatures in the islands, from the low 70s to the mid-80s.
During the warmer months, the average temperature during the day is in the high 70s or low 80s, and the water temperature is from 76-83 degrees. The skies are generally clear, with sporadic rain and calmer seas.
From May to December the air temperatures are slightly lower, with the average temperature in the low to mid 70s. There can also be a mist in the air called the “garua,” and the ocean can be slightly choppier, though it rarely gets very rough in the Galapagos at any time of year. The colder Humboldt Current predominates and water temperatures drop to an average of 65-72 degrees. Again, please note that these historical patterns have become much less predictable in recent years!
To see a suggested itinerary combining these two magnificent locations, please see our Machu Picchu & Galapagos Itinerary. It combines some of the top highlights of both Peru and the Galapagos Islands in one trip.