Due to its geography and topography, the climate in Machu Picchu's National Sanctuary varies widely. Its mountain peaks, at around 6,270 meters above sea level, show very low temperatures, and the lower areas, averaging around 2,000 meters above sea level, have a milder climate.

Temperatures in the Machu Picchu area vary from the upper zone to the canyon bottom, though, generally speaking, the climate is mild, showing mainly subtropical features: it is warm and humid - hot in the daytime, and cool at night.

Located in a subtropical area, it has lows ranging from 8º to 11.2º Celsius, though it can reach 0º Celsius at the higher altitudes. June and July share the coldest mornings, reaching -2º Celsius (28.4º F). During the rainy season (November through March), the temperatures reach 16 to 18° Celsius in the daytime and below 0º Celsius at night.

Maximum temperatures range from 20 - 22º Celsius. The hottest days (not very frequent), can bring temperatures reaching about 26º Celsius (78.8º Fahrenheit). The dry season (April- October) brings temperatures reaching 23º Celsius in the daytime and 0º Celsius at night.

RAIN AND HUMIDITY

• While the rainy season in Machu Picchu lasts from December to March, the dry and sunny season lasts from April to November or December. During the springtime, September brings a special gift of gorgeous, subtropical landscape.
• The rainy months represent around 80% of the annual rainfall average, which ranges from 1,600 to 2,300 mm. The average humidity is 77% during dry months and 91% during rainy months.
• During the rainy season, from September to April, frequent downpours are commonly followed by a blue and clear sky and bright sun. However, as its location is on the brow of the Amazon forest, rains can come in any month of the year, even during the dry season, from March to December.

WHEN TO GO AND WHAT TO WEAR

• The best months to visit Machu Picchu are May and June, since they are the mildest ones. Always try to bring along an umbrella or raingear, sunscreen and bags to protect your photographic equipment.
• Broadly speaking, the days are warm and the nights cold. You have to be prepared for fluctuating temperatures. It would be ideal to bring along a sweater, mittens and a wind-jacket, inside a small backpack. During the day, you can wear long-sleeved cotton shirts and comfortable trousers to move around easily. During the dry season (May-November), the sun forces you to wear sunglasses and a hat, and apply sunscreen.
• You should bring bottled water. During the rainy season (December- April), it is advisable to bring boots to walk comfortably, since the ground gets too muddy. To protect them from rain, you should also carry your personal belongings and ID in a plastic bag inside the backpack. Be sure you always bring an extra long-sleeved shirt.
• Since Machu Picchu has a warm climate, there are plenty of insects and mosquitoes, which mostly appear during sunny days, and whose bites produce skin irritation. We recommend you take insect repellent.
• If you are going on the Inca Trail to Machu Picchu, your travel agency will give you the necessary equipment.
• You should bring along a sleeping bag, a backpack, a multipurpose knife, motion sickness pills, universal snake-poison serum, and bottled water.

ALTITUDE SICKNESS IN MACHU PICCHU

Also known as mountain sickness, this is basically a consequence of the shortage of oxygen. It is suffered mainly by people who do not acclimatize within a day or two, at an altitude of over 2,000 meters above sea level. Even though the effects are different in every person, almost all tourists who arrive at Cusco by plane are prone to suffering altitude sickness. In fact, there are some people who are never affected by altitude at all. There are various symptoms that generally show within the first 48 hours of ascent, among which we can mention headaches, nausea, loss of appetite and even a feeling of breathlessness, sleep problems and palpitations, among others.

Prevention

The best way to prevent altitude sickness is by making a gradual ascent. It is essential for travellers to Cusco to carry out their activities in a gradual way. It is highly advisable to rest for a day, have a light meal and enjoy the delicious mate of coca, a brew that is effective against mountain sickness.

If you have some time available and can spend the first nights of your trip to Cusco in the Holy Valley, you will have fewer chances of being affected by altitude sickness.