Peru is the 19th-largest country in the world by area at 1.29 million km² and has population of 34 million, sitting on the western side of South America. The country borders Ecuador and Colombia (north), Brazil (east), Bolivia (southeast), Chile (south), and the Pacific Ocean (west). Peru has extraordinary geographic diversity — the country contains three distinct climate zones: the famous Costa (Pacific coast — arid desert), the famous Sierra (Andes Mountains rising over 6,000 m), and the famous Selva (Amazon rainforest — covering 60% of Peru). Peru was the famous heartland of the Inca Empire (1438-1533), the largest empire in pre-Columbian America at its peak. The famous Spanish conquistador Francisco Pizarro overthrew the Inca Empire in 1532-1533; Peru gained independence in 1821. The country has rich Indigenous heritage (45% of Peru identifies as Indigenous), the famous Quechua language (still spoken by 4 million Peruvians), and extensive pre-Columbian archaeological sites.
Major destinations include Machu Picchu (UNESCO World Heritage — the famous Inca citadel at 2,430 m elevation, one of the New Seven Wonders of the World, "rediscovered" by Hiram Bingham in 1911 though always known to local Quechua people, with the famous Huayna Picchu peak and the famous Inti Punku "Sun Gate"), Cusco (the famous Inca capital at 3,400 m elevation — UNESCO World Heritage with extensive Inca stonework including the famous Sacsayhuamán fortress, the famous Plaza de Armas, the famous Twelve-Angled Stone, the famous Qoricancha Temple of the Sun), the famous Sacred Valley of the Incas (with the famous Ollantaytambo and Pisac ruins, the famous Maras salt mines, the famous Moray agricultural terraces, and the famous indigenous markets), the famous Inca Trail (the famous 42 km 4-day trek to Machu Picchu — permits limited to 500 daily including porters and guides, sells out months ahead), Lima (the capital — population 11 million metropolitan, with the famous Historic Centre — UNESCO World Heritage, the famous Miraflores and Barranco coastal districts, and the famous Peruvian culinary scene — Peru is consistently ranked among the world's top culinary destinations with Lima's restaurants including Central, Maido, and Astrid y Gastón regularly featured in World's 50 Best Restaurants), Arequipa (UNESCO World Heritage with the famous Santa Catalina Monastery — a 20,000 m² Spanish colonial convent containing a "city within a city"), the famous Colca Canyon (the famous Andean Condor viewing destination, twice as deep as the US Grand Canyon), Lake Titicaca (the famous "highest navigable lake in the world" at 3,812 m, with the famous Uros floating reed islands and Taquile Island), the famous Nazca Lines (UNESCO World Heritage — the famous prehistoric geoglyphs visible only from aircraft), Iquitos and the Peruvian Amazon (with extensive jungle lodges and the famous pink river dolphins), Puerto Maldonado and the famous Tambopata National Reserve (the famous Amazon biodiversity hotspot with extensive wildlife), the famous Rainbow Mountain (Vinicunca) at 5,200 m, the famous Huacachina desert oasis, and the famous Paracas National Reserve (with the famous Ballestas Islands — Peru's "Galápagos").
The coast (Lima, Paracas) has its own pattern of fog and sunshine. The Andes (Cusco, Machu Picchu, Lake Titicaca) operate on a dry-and-rainy season cycle. The Amazon (Iquitos, Puerto Maldonado) is wet most of the year. Each region has its own optimal months, and the famous Inca Trail closes entirely for one month every year.
Quick verdict
Best for Machu Picchu, Cusco, Inca Trail: May through early September. Dry season, clear skies, peak views.
Best for the Amazon: May through October. Lower water levels expose more wildlife on riverbanks.
Best for the coast (Lima, Paracas, Nazca): December through April. Sunny coastal summer.
Best for budget travelers: April and October-November. Shoulder months, lower prices, mostly good weather.
Avoid if you can: February in the Andes (heaviest rain, Inca Trail closed for the whole month).
The Inca Trail's closure window
One of the most important facts for trip planning: the classic Inca Trail closes for the entire month of February every year for maintenance. Alternative treks (Salkantay, Lares, Choquequirao) remain open but are also less pleasant in February due to heavy rain. If the Inca Trail is your goal, plan around the May-September dry season window.
Permits for the Inca Trail are strictly limited — 500 per day including porters and guides, meaning only about 200 hikers per day. They sell out months in advance for peak season. Book 6-9 months ahead for May-September.
Dry season (May to September): peak for the highlands
This is the most popular time to visit Peru. Cusco and Machu Picchu enjoy dry, sunny days at 18-22 °C with cold nights (often near freezing at altitude). The famous postcard view of Machu Picchu with crystal-clear skies is most reliable May through August. Trails are dry and well-defined.
June and July are peak season. Cusco fills with travelers; permits sell out earliest for these months. Inti Raymi (Festival of the Sun, June 24) is the Inca Empire's reenacted festival — atmospheric but adds crowds. The Sacred Valley is in its visual prime.
August continues peak conditions. By late August, the dry season's dust accumulates and views become slightly hazier. September is the last month of reliable dry conditions; by month's end, occasional showers start appearing.
The Amazon during dry season has its own appeal. River levels drop, exposing sandbars and beaches. Wildlife concentrates at remaining water sources. The famous oxbow lakes of Tambopata and Manu are at their most accessible. Birdwatching is excellent. Mosquitoes are reduced compared to wet season.
Wet season (October to April): challenging in the Andes, brilliant on the coast
October sees the start of rain in the highlands. The first half is still mostly fine; by late October daily afternoon showers become common. November sees real rain ramp up. Crowds drop sharply. Permits are easy to get for the Inca Trail. Prices ease from peak.
December through March is full wet season in the Andes. January and February have the heaviest rain — Machu Picchu can be cloud-shrouded for days. Trails become slippery; landslides occasionally close roads. The famous mountain views are unreliable.
Conversely, the coast (Lima, Paracas, Nazca) is in its best season December through March. Lima emerges from its grey winter fog — finally seeing reliable sunshine. Daytime 22-27 °C. Beaches at Paracas and the Ica coast are in their prime.
The Amazon in wet season is at high water — boats can navigate areas inaccessible in dry season, giving access to flooded forest experiences. Photography of the canopy from above is best with high water. But beaches are submerged and some trails impassable.
Lima's unusual weather
Lima is one of the most unusual coastal cities in the world climatically. From May through November, the city is shrouded in a persistent low cloud layer called "garúa" — a fog/drizzle combination that almost never produces real rain but keeps the city overcast and cool (15-19 °C) for six straight months. This is winter in Lima despite the moderate temperatures.
December through April is Lima's summer. The garúa lifts, sun returns, daytime climbs to 22-28 °C. This is also when Lima's celebrated food scene comes alive with outdoor dining and beach day-trips.
If your primary Peru focus is Lima and the coast, January through March is genuinely the best time. If you're combining with the Andes, plan to accept Lima's gloom in shoulder months — you'll be inside museums and restaurants anyway.
Regional summary
Cusco, Machu Picchu, Sacred Valley: Best May-September. Inca Trail closed February.
Inca Trail and alternative treks (Salkantay, Lares): May-September peak.
Amazon (Iquitos, Puerto Maldonado, Manu): Dry season May-October better for wildlife concentration.
Lima: Best December-April. Gray and foggy May-November.
Coast (Paracas, Nazca, Trujillo): Best December-April.
Colca Canyon / Arequipa: Best April-November.
Lake Titicaca / Puno: Best May-October.
Altitude considerations
Most Peruvian highland destinations sit at 3,000+ meters. Cusco is at 3,400 m. Machu Picchu sits at 2,430 m. Lake Titicaca is at 3,810 m. Acclimatization matters — most travelers arrive from sea-level Lima and need 2-3 days at altitude before strenuous activity. Coca tea and slow movement help.
Festivals and events
Inti Raymi (June 24) — Festival of the Sun in Cusco. Corpus Christi (June) — religious processions in Cusco. Independence Day (July 28-29). Carnival (February or March). Mistura (Lima food festival).
Verdict by traveler type
First-time visitor doing Lima + Cusco + Machu Picchu: May or September.
Inca Trail hiker: May or September.
Amazon focused: June-September for wildlife concentration.
Photographer: May-June for clearest mountain views.
Budget traveler: Late April or October.
Coastal / Paracas focused: December-March.
Family travel with kids: May-September for dry highland weather.
Bottom line
Peru's three-zone geography forces real trade-offs. The May-September window is the most reliable for the Andes and Amazon combination but means accepting Lima's gloom on the coast. Most first-time visitors should prioritize the highlands and aim for May or September — slightly less crowded than peak July-August but with nearly identical weather conditions.