Iguazú Falls drops 275 individual cascades along a 2.7km horseshoe shared between Argentina and Brazil, with the Devil's Throat at the head of the fall and the Triple Frontier where Argentina, Brazil, and Paraguay meet at the Paraná River.
Falls at high flow without summer's overwhelming crowds, autumn temperatures pleasant for the loop walks, and the rainforest still green from the wet season.
Cooler dry season with the falls at moderate flow, Devil's Throat boardwalk accessible, and the Misiones jungle wildlife visible without afternoon storm interruptions.
Spring shoulder with rising flow as wet season returns, butterflies at peak across the falls trails, and Argentine Independence Day July 9 aside, lower visitor density.
Wet season with the falls at maximum flow but afternoon storms common, hits 35°C with humidity, and crowds at peak with Argentine and Brazilian summer holidaymakers.