Peru is a country with a variety of weather, we count with a Peru weather guide, where you can find more information and know when in the best time to travel to Peru is.
The Mountain Highlands (Cusco, Lake Titicaca, etc)
Mid April – October.
This period is the dry season, with hot, dry days and cold, dry nights, often hovering just above freezing, particularly in June and July. May is perhaps the best month with the countryside exceptionally lush, yet with superb views and fine weather. Peru’s high season is from June to August which coincides with the dry season and summer holidays in North America and Europe.
November – Mid April
This is the wet season with most rain in January and February. It’s usually clear and dry most mornings with outbursts of heavy rain in the afternoons. The daily temperatures are typically mild with only a small drop at night.
The Inca Trail is much less crowded during this period and there’s a more abundant fresh water supply, but of course be well equipped for the rain. You’ll also find some roads may become impassable particularly when trying to visit villages off the beaten track.
The Coast (Lima, Nasca, Arequipa).
December – April
This is summertime on the coast where the weather is hot and dry . Temperatures on average range from 25 – 35°C. There is little or no rain during these months.
May – November
From May to November the temperature drops a bit and you’ll find blankets of sea mist engulfing the coast from the south right up to about 200 km north of Lima.
April – October
This is the ‘dry’ season with daily temperatures averaging 30–35°C. However cold fronts from the South Atlantic are common when the temperatures can drop to 15°C during the day and 13°C at night.
The dry season is the best time to visit the jungle regions … there are fewer mosquitoes and the rivers are low. It’s also a good time to see nesting and to view the animals at close range, as they stay close to the rivers and are more easily seen.
November – March
This is the wet season, hot and humid, when you can expect heavy rain at anytime. It only rains for a few hours at a time, so it’s not enough to spoil your trip. Wellington boots are a must though, as some of the jungle trails can become small rivers.
For more information you can see the official page of weather http://www.senamhi.gob.pe (Spanish, partial in English)
Machu Picchu ( Cusco )