Between June and October, temperatures can drop to almost about 3º or less at night, but unlike from April to December, there are no heavy rains.
Generally speaking,
Cusco's weather can be cold, but rarely freezing.
The average annual temperature is 12ºC, ranging from an average morning temperature of 18º and nighttime temperature at around 6º
WHEN TO GO TO CUSCO
The ideal time to visit
Cusco is between June and October, when you can enjoy brilliant sunshine from very early in the day, as is the case throughout the Peruvian highlands all year round. Nevertheless, it can get rather chilly in the shade, thus you should always keep a warm garment with you when you're out and about.
Another important reason for visiting
Cusco in June is the Inti Raymi or "Celebration of the Sun". This event is a reenactment of the most important ceremony from Inca times, when the Inca Emperor venerated the Sun God, and implored Him to grant abundant harvests and eradicate famine from the Empire.