When to go — Sacred Valley

The optimal window for Cusco and Machu Picchu is the Andean dry season, May to September. The sky stays blue, trails are in perfect condition for treks, visibility from Machu Picchu is maximum, and daytime temperatures are pleasant (15-22 °C at Cusco, 18-25 °C in the Sacred Valley, 14-22 °C at Machu Picchu). Andean nights are however cold (0-5 °C at Cusco, down to -5 °C in some Sacred Valley villages) — warm clothing essential.

It's also the high tourist season. Machu Picchu being limited to 4,500 visitors/day, book your ticket 3-6 months ahead for June-August. PeruRail/IncaRail trains Ollantaytambo-Aguas Calientes fill quickly — book 1-2 months ahead. The 4-day Inca Trail (500 permits/day) must be booked 6 months ahead for high season departure. The most popular hotels in Cusco (Belmond Hotel Monasterio, Inkaterra La Casona, Palacio del Inka) and Aguas Calientes (Sumaq, Inkaterra Machu Picchu Pueblo, Sanctuary Lodge) must be booked months ahead.

June marks the tourist peak with Inti Raymi on 24 June at Cusco — Peru's biggest cultural festival, modern recreation of the great Inca winter solstice festival, gathering over 100,000 spectators on the Sacsayhuamán esplanade. It's an exceptional experience but Cusco is then saturated — book everything 6 months ahead. July-August are the driest and busiest months (North American and European school holidays).

April, October and November correspond to shoulder season: rates down 20-30%, much-reduced crowds at Machu Picchu and on the Inca Trail, generally favorable conditions with some residual rain. It's our price/conditions recommendation for flexible travellers. The wet season (December to March) brings frequent rain in the Andes — muddy trails, morning fog on Machu Picchu, often cloudy skies. The Inca Trail is closed in February for annual maintenance. But it's also the absolute low season: rock-bottom rates, much-reduced crowds, spectacular green landscapes.