Cusco Region
Cusco Region Geography & Climate
Geography
Cusco region spans an extraordinary vertical range — from Andean glaciers to Amazon rainforest — within a relatively small area, and altitude governs everything.
The city and the high plateau
Cusco sits at about 3,400 metres in a bowl surrounded by hills, high enough that most arrivals feel it. The surrounding puna grassland runs above 4,000 metres, grazed by llamas and alpacas and too high for most crops.
The Sacred Valley
The Urubamba river runs roughly north-west through a valley at 2,800 to 3,000 metres — several hundred metres lower than Cusco, which makes it warmer, more fertile and much easier to sleep in on arrival. The Inca understood this and sited their agricultural estates here.
The gorge and the cloud forest
Below Ollantaytambo the river cuts down sharply into a steep gorge, and the vegetation changes within an hour’s travel from dry highland scrub to bromeliads, tree ferns and orchids. Machu Picchu sits at about 2,430 metres in this transitional zone, which is why it is so often in cloud.
The peaks
Salkantay at 6,271 metres and Ausangate at 6,384 are the great mountains of the region, both revered as apus, and both surrounded by glaciers that are retreating measurably.
Terracing
The valley sides everywhere are stepped with andenes, agricultural terraces built by the Inca and their predecessors, which flatten the slope, hold soil and water, and create warmer microclimates than the raw hillside. Many are still farmed. At Moray the terracing is concentric and set into a natural depression, with a temperature difference of several degrees between top and bottom — most probably a place for trialling crops at different altitudes.
Beyond
The region’s northern districts drop into the Amazon basin proper, and Manu national park descends from 4,000 metres to under 300, giving it one of the highest species counts of any protected area on earth.
Climate Patterns
Cusco’s climate is set by altitude rather than latitude, and the seasons are dry and wet rather than warm and cold.
The dry season
May to September is the visitor season. Days in Cusco reach 19 to 21°C with strong sun and very low humidity; nights fall to near freezing, and June and July regularly drop below zero. The sky is clear and the mountains are out. The Sacred Valley, several hundred metres lower, is a few degrees warmer both day and night.
The wet season
November to March brings daily afternoon rain, often heavy, with January and February wettest. Temperatures are actually milder overall — nights are warmer and days a little cooler — and the landscape is green. Cloud sits on the peaks, and Machu Picchu is frequently invisible in the morning and clear by midday, or the other way round.
Altitude and sun
The thin air at 3,400 metres means intense ultraviolet regardless of temperature, and a cloudy day will still burn you. It also means the temperature swings enormously between sun and shade — layers matter more than a warm coat.
Machu Picchu’s own weather
At 2,430 metres in a cloud forest, it is warmer, much more humid and considerably wetter than Cusco, and rain is possible in any month.
Retreating glaciers
The tropical Andes hold most of the world’s tropical glaciers and Peru has lost a very large share of its ice cover since the 1970s. In this region the effect is visible on Ausangate and Salkantay and is a practical matter as well as a scenic one: highland communities depend on glacial melt for dry-season water, and the Qoyllur Rit’i pilgrimage stopped cutting ice from the glacier for exactly this reason.
Landslides
Heavy rain periodically closes the rail line to Aguas Calientes; the 2010 floods cut it for months.