Climbing in Peru offers the best bang for your buck in comparison to other great ranges of the world. While mountains like Denali or the Himalayas can cost over $10,000 for an expedition and take over a month, Peru has the most accessible peaks over 20,000 feet anywhere in the world and is quite cheap in comparison. The scenery is loaded with colors contrasting the green pastures, turquoise lagoons and brilliant white peaks, not just gray rock on your approach to base camp. Several valleys in the Cordillera Blanca offer the opportunity to climb big peaks from the same base camp. This lets you do more climbing for less money and time invested.

The best time for mountain climbing in Peru is the South American winter; April to September, with the driest months being June and July. Early in the season there is more accumulated snow left over from the rainy season, by August the glaciers are usually quite dry and more crevasses will have opened up. These conditions can affect route conditions over the season, for example: the normal routes on some mountains like Huascaran or Chopicalqui can be impassable late in the season due to a large crevasse that has opened up. In my experience the best time to climb your project peak in Peru is July 15^th to August 15^th.

In the mountains of Peru, the rainy season is November to March.  Trekking is still fine to do in these months but be prepared for the rain. During this time, it is not recommendable to climb because there is much more weather to deal with. I have climbed 5,000meter peaks during these months many times, when the weather opens for a few days, but you have to be conscious of the storms and being prepared to retreat.

If you are going to the lowland jungle (below 1000 meters above sea level) then yes, it is good to have your yellow fever vaccination. Malaria pills are a good idea too if you are going on a trip deeper in the jungle. But if you are going into the highlands or even the cloud forest around Machu Picchu you do not need these. General vaccinations needed are typhoid and hepatitis A.

It is very important to acclimatize properly. If you are just arriving to Cusco, I recommend at least 3 full days in Cusco (3,300mts/10,824ft) or Huaraz, before doing a serious trek or trying a peak higher than 5,000mts.
It is recommendable to climb a peak of 5,500 meters, before a 6,000 meter peak if you have the time. If you are already well acclimated, it is possible to go directly to climb an easier 6,000mts peak like Ausangate, Chumpe or Yayamari. These guidelines should be regarded as the minimums. Often people have a tight schedule and want to do as much as possible with their time, but acclimatization is important for you to be able to accomplish your goals.

Temperatures in the mountains during the day can vary greatly depending on weather conditions. Above 4,000 meters in altitude, If the sun is out and there is no wind, it can be up to 65F (18C) during the day. At night during clear weather it can get down to 23F (-5C).
Above 5,000 meters in altitude, for example at the moraine camp (5,500m) of Ausangate it can get down to 14F (-10C) during the night. Above 6,000m it can get down to -4F (-20C) and even colder when you factor in the windchill.

There is much more solar radiation at altitude in Peru, Ecuador and Bolivia than other places because they are tropical ranges. It is very important to protect your skin and eyes from these conditions so that you don’t go snow blind after climbing. Anyone who climbs in the Andes needs good sunglasses and we suggest to have a brimmed hat and plenty of sunscreen, even for your lips.

We use the French alpine system to grade the routes on a mountain. This system is widely used to give a good idea of the overall difficulty of the complete route based on all factors of the final approach, ascent and descent including length, altitude, danger, commitment, and technical difficulty. This way you can better plan and train for a climb.
 
F: Facile/easy. Rock scrambling or easy snow slopes; some glacier travel; often climbed rope less except on glaciers.
PD: Peu Difficile/a little difficult. Some technical climbing and complicated glaciers.
AD: Assez Difficile/fairly hard. Steep climbing or long snow/ice slopes above 50 degrees; for experienced alpine climbers only.
D: Difficile/difficult. Sustained hard rock and/or ice or snow; fairly serious stuff.
TD: Tres Difficile/very difficult. Long, serious, remote, and highly technical.
ED: Extremement Difficile/extremely difficult. The most serious climbs with the most continuous difficulties. Increasing levels of difficuly indicated by ED1, ED2, etc.

In Cusco:
 There are no peak fees for climbing any single mountain in Peru.
However, there are fees for camping in many areas. These fees are usually minimal, counted by the amount of tents or horses you are using (3, 5, or 10 soles per). Usually they are paid directly to someone in the local village or community on whose land you are camping. In some areas like the entrance to the Ausangate (Vilcanota) Range there is a control point where they charge 10 soles to enter the area as a tourist.
 
Entering the Cordillera Vilcabamba through KM82 at the start of the Inca Trail is not allowed unless you get a permit for hiking the highly popular Inca Trail with an agency. Luckily there are many other places to access the Vilcabamba. The closest entrance to Salkantay is through the town of Mollepata where the fee is 10 soles for entrance to the area.
 
In Huaraz:
 The Cordillera Blanca range is part of the Parque Nacional Huascaran (Huascaran National Park). The entrance to the park costs 150 soles as of 2019 and is valid for 3 weeks for trekking or climbing inside the park. This entrance ticket can be bought in Huaraz ahead of time. The park only actually controls the most popular entrances to the park, not all of the valleys. But unless you are going well off the beaten path, you will be asked for this ticket at the entrance to the valley.
 
Cordillera Huayhuash:
 There are no peak fees for climbing in the Huayhuash, but each community around the mountains charges their own fee (usually 10-20 soles per person) for camping in the area.
 
In Arequipa:
 There are no peak fees for hiking the volcanoes in Arequipa.

In Cusco:
 There is no organized high mountain rescue in Cusco and there are few guides even capable of making a rescue on a glacier/mountain that live in the area. The Police have a rescue unit but they will not go higher up on a glacier to rescue you. Even so, any rescue that may be organized will probably be too late to actually save you from dying if a serious accident happens. Therefore, it is important to have an evacuation plan organized by your Guides team and Arrieros. It is beneficial to work with local people who live closest to the area who have the best chance of getting someone out in case of an accident.
 
In Huaraz:
 In Huaraz the high mountain police are supported by the fact that there are many more mountain guides available to make a rescue, since the tourism of Huaraz is based on trekking and climbing. There is a more organized response to an accident and call for help, but should not be compared to somewhere like the Alps where helicopters are used often