Since the seasons are opposite in the southern hemisphere, October falls in the middle of spring in northern Argentina and southern Brazil, where Iguazú Falls are located. This is the wettest month in the region, with up to ten rainy days, on average: there's a reason that gift shops in Iguazú National Park sell ponchos and emergency rain gear (though to be fair, the gear is just as much for travelers embarking on boat rides towards the falls—if you don't want to get drenched, it's a practical option).
Expect highs in the low 80s and lows in the lower to mid-60s in October. After a break in humidity levels over the winter, the weather starts getting sticky heading into spring. This is the jungle, after all! The days are getting longer in September, too, giving you more time to enjoy being outdoors in the magnificent region around Iguazú Falls.
Crowds & Costs
After a few slower winter months, tourism to Iguazú starts picking up in October: nothing like what you'll experience in summer (or during winter break for Argentines and Brazilians in July), but you'll want to think ahead when it comes to travel plans. Get your plane tickets as far in advance as possible, and reserve hotel rooms well ahead of time, especially if you're visiting on a weekend.
That said, hotel rates are standard at this time of year—you might even see mid-week promotions on accommodations. You'll see an average number of visitors in the parks, making it a good time to visit. Still, consider reserving a rental car ahead of time if you think you'll need one, as rental companies sometimes run low on vehicles on busy weekends.
What To Do
Hike, raft, motorboat, bird-watch, picnic: October is a good time of year for all the activities the national parks have to offer, thanks to moderate temperatures and reasonable crowds. The only real factor that could affect your plans is rain—this is the wettest time of the year at Iguazú, so you should be prepared for quickly changing weather (and the mosquitoes that sometimes come along with it).
On the other hand, the weather makes it a fine time to take the 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—but depending on the forecast when you visit, you'll be prepared to get wet, anyway! 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).
Watch your step—catwalks can get slippery—as you wind your way around the waterfalls' cascades, stopping at viewing platforms and lookout points along the way, where you'll enjoy relatively unobstructed views of key natural attractions like Bossetti Jump and Garganta del Diablo. The cloudy weather, as a plus, creates ideal conditions for photography.
What To Look For
While on a boat (either the Gran Aventura or the lower-key rafting excursion offered by the same outfitter), keep an eye out for herons, kingfishers, black-collared swallows, and birds of prey. On the hiking trail, look for colorful toucans and hummingbirds, plus vibrantly hued butterflies and howler and capuchin monkeys. If you're lucky, you might even spot the elusive jaguar: they're drawn to rivers and streams. If you're able to join 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.
Apart from wildlife, there's a major advantage to visiting Iguazú during the rainy season: the river level is high, so the falls look especially dramatic. Enjoy the spectacular views—just be careful on the hiking trail.
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 October? 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.