December marks the end of spring and the beginning of summer in the southern hemisphere. That means warm to hot temperatures, moderate to high humidity, and occasional early summer storms in northern Argentina and southern Brazil, where Iguazú Falls are located. Expect highs in the upper 80s into the low 90s and lows in the upper 60s and lower 70s—you may not need a jacket after dark, but it's wise to bring layers, just in case. Generally speaking, December is characterized by pleasant weather.
The end of the year brings some rainfall to the region, but mostly in the form of passing summer storms. Even if you're caught unaware, you can buy an inexpensive poncho at one of the gift shops in the national park. The days are long in December, giving visitors extra time outdoors. It's also a great time to take advantage of the pool at your hotel—after a long day of hiking, you'll probably be ready to take a dip.
Crowds & Costs
Iguazú attracts lots of visitors in December, especially towards the end of the month, when vacation begins for Brazilians and Argentines. As summertime begins in Argentina and Brazil, lots of people go on vacation in their own countries—and a wave of travelers come from the US and Europe, too, escaping the cold at home.
Book flights and accommodations well ahead of time, and prepare to wait in line at ticket counters, restaurants, the airport, and the parking lots at both national parks. Around the holidays, you'll notice that prices are higher at hotels—and that some places are fully booked with weekenders and people traveling on package trips—but it's not much of a problem for the first few weeks of the month.
What To Do
December is a great time for hiking and wildlife viewing on jungle trails. Get an early start to beat the heat, and make sure to use the train system that transports you between the park's entrance and major attractions like La Garganta del Diablo (a dramatic lookout point perched high over the cascades) and the picturesque Bossetti Jump.
The sun is intense at this time of the year, so stay in the shade and think about getting out on the river—it's an ideal time to take an exhilarating Gran Aventura boat ride that takes you close to the base of the falls. You'll get drenched from the spray of the falls, which feels great on a hot day. Book online or get more information at the Visitors Center, which is also the departure point for the tour (which involves transportation in an all-terrain vehicle to the riverside point where the boats are docked).
If you happen to be at Iguazú at the end of the year, when crowds surge, think about taking a hike along Macuco Trail. Far fewer tourists venture there, so the round-trip hike towards the river is a nice option: just remember to bring plenty of water and mosquito repellant.
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What To Look For
Rainfall makes the level of Iguazú River rise, so the end of the year—several months into the rainy season—is a thrilling time to view the falls. Enjoy the spectacular views, but be careful on the hiking trail, as catwalks can get slippery when wet.
It's also a good time for wildlife viewing. Indigenous to the jungles around Iguazú, the Yaguareté (jaguar) is one of the largest cats on the globe. It would be rare, though not impossible, to spot one walking through the forest. Easier to spot in the wild are several varieties of toucans: just look up in the trees for their colorful beaks. Look for bright green and red hummingbirds and plush-crested jays—they're amazingly unafraid of human visitors.
You'll see howler and capuchin monkeys climbing through the branches that frame hiking trails, plus a colorful array of butterflies. If you board a boat for the Gran Aventura tour, look for herons, kingfishers, and birds of prey. On a night tour, you'll have the chance to see a wide variety of owls, including the tropical screech-owl, as well as nighthawks and other creatures that only come out at night.
Events & Activities
Walks in the Moonlight: Iguazú National Park offers guided nocturnal tours on five evenings each month. The schedule depends on the lunar calendar. Sign up ahead of time for the chance to see the park’s natural attractions under the moonlight, plus owls and other creatures that only come out at night. Several departures are available (7:45, 8:30, and 9:15pm) and reservations are required.
Visiting Iguazú Falls in December? Check out these itineraries.
Buenos Aires & Iguazú Falls Experience - 7 Days Begin your journey in Buenos Aires and head to Iguazú Falls to see the jaw-dropping beauty of the largest waterfall system in the world. You'll get to experience the falls from both Argentina and Brazil, and take in a tango show in the capital city.
Ultimate Iguazú Falls Experience - 4 Days This four-day getaway to Iguazú Falls takes you into the heart of one of Argentina’s most prized destinations. Then, you'll experience another side of the falls from Brazil, with expansive, panoramic views.