The best time of year to visit Machu Picchu is from June to October. During these months you should get plenty of bright, warm sunshine in the day – perfect for enjoying the ancient ruins. However, the nights can still be a chilly 10C, so make sure you bring warmer clothes for the evenings.
If you visit from December through to June, the weather is far more dramatic, with sudden heavy rain clearing into spells of brilliant sunshine.
Whenever you choose to travel it is best to have an umbrella or raincoat, as the weather in the Andes can be quite changeable. A good pair of walking shoes with a reliable grip is also recommended, as the Machu Picchu can get pretty slippery after a downpour.