What the official source says about the weather
The SENAMHI document Climas del Perú classifies the climate of the Cusco highlands as rainy with a moisture deficit in autumn and winter. For the Urubamba valley it speaks of temperate climates with dry autumns and winters. It gives no visiting calendar: use it to understand the general pattern and check the forecast before you go.
What changes in the visit depending on the date
The circuit and the route are chosen when you buy the ticket, and routes 1-C, 1-D, 3-C and 3-D are listed as available only in high season. The official website does not say on that page which months count as high season, so look at what Tuboleto offers for your date.
- Route 1-C: Intipunku Gate
- Route 1-D: Inka Bridge
- Route 3-C: Great Cave
- Route 3-D: Huchuypicchu
How to choose between a one-day and a two-day excursion
The date also decides how many days you need. With the one-day excursion you return to Cusco the same day, according to the tour listing. The two-day one includes a night with breakfast and gives you more margin if the weather changes. On the one or two days page you can compare them.