Foz do Iguaçu weather in December

December in Foz do Iguaçu: sweltering, soaked, with clean air — a gamble, with 13 rainy days.

Updated September 2026 · climate normals from ERA5 reanalysis

Foz do Iguaçu🇧🇷 Brazil · Southern Brazil & Iguazú · National park55
  1. 51Jan
  2. 54Feb
  3. 59Mar
  4. 72Apr
  5. 74May
  6. 80Jun
  7. 87Jul
  8. 81Aug
  9. 75Sep
  10. 66Oct
  11. 65Nov
  12. 55Dec

#10 of 12 months in Foz do Iguaçu · #1064 of 1413 destinations to visit in December · comfort 55/100 (tier D)

Days
32°C
Nights
21°C
Wet days
13
Sun
11.1 h
Humidity
73%
Daylight
14 h
Foz do Iguaçu, Brazil
Photo: Jean Alves · Pexels

Traveller notes on Foz do Iguaçu in December

Other months in Foz do Iguaçu

Foz do Iguacu-forum threads on February weather describe this as genuinely hot and humid, posters calling the Brazilian side's panoramic walkway a real highlight for seeing the full sweep of the falls across the canyon. Regulars call water volume typically strong this time of year, the color sometimes running reddish-brown after heavy rain upstream, a natural effect rather than pollution. Posters describe the mist at several viewpoints as genuinely soaking, ponchos available for rent though many visitors accept getting wet. Regulars recommend a half day on the Brazilian side as sufficient, the Argentine side offering the more extensive trail network for a full day. Posters call a sudden afternoon thunderstorm a real possibility, checking the forecast that morning standing advice. Regulars recommend comfortable clothes regardless of which side you visit. The record: 32.9C days feeling like a punishing 38C, 21.8C nights, 115.5mm across nearly 12 days and 75 percent humidity.
FozDoIguacuFebruaryRegular · February · 1 month ago · Read more on Tripadvisor ↗
Foz do Iguacu-forum threads naming the best months for the falls call March a genuinely strong pick, peak summer crowds thinning while water volume typically stays strong from the wetter months just behind. Posters describe daytime conditions as comfortably warm rather than punishing, evenings cool enough that air conditioning becomes unnecessary most nights. Regulars call the wetter pattern running November through early in the year as generally easing off by March, though a passing system remains possible. Posters recommend flexible plans, a shower rarely lasting long enough to disrupt a full day. Regulars describe visibility and mist as generally favorable this time of year, the full width of the falls usually clear from the main walkways. Posters call March one of the more comfortable months for the Brazilian side specifically. The record: 31.8C days feeling like a punishing 35C, 20.9C nights, an extraordinarily high 122.3mm across nearly 12 days and 76 percent humidity.
FozDoIguacuMarchRegular · March · 1 month ago · Read more on Tripadvisor ↗
Foz do Iguacu-forum threads on September confirm this sits toward the start of a favorable stretch, comfortable temperatures and generally settled conditions on the Brazilian side of the falls compared to the more extreme months. Posters describe water levels as capable of swinging within the same week, one visitor reporting locals calling the river low and the falls comparatively dry just before arrival, only for an upstream system to bring the falls back to a misty, dramatic full flow by the time they visited. Regulars call this unpredictability part of the appeal, no two visits looking quite the same. The Brazilian side's panoramic walkway is repeatedly named the better overview compared to the closer, wetter Argentine trails, both sides commonly combined into a single trip. Posters call September crowds noticeably thinner than peak holiday periods. The record: 29.5C days feeling like a punishing 32C, 16.6C nights, 71 percent humidity and 7.1 hours of sun.
FozDoIguacuSeptemberRegular · September · 1 month ago · Read more on Tripadvisor ↗
August sits at the end of the drier half of the year, and the forum's framing is a trade: sunshine most days, and falls that are not at their strongest, since the lowest water levels fall in July and August. How low depends on rain upriver rather than on the calendar, and the variance is wide - the same month has produced complaints of poor volume and reports that the falls were stunning regardless. The compensations regulars name are cooler air and easier walking on the trails. Our row supports the drier reading without making August dry: 94.1mm over 7.2 precipitation days. The record: 26.5C days, 13.9C nights, humidity 71 percent and 8.8 hours of sun.
DependsOnRainUpriver · August · 1 month ago · Read more on Tripadvisor ↗

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Foz do Iguaçu climate normals — December

Daytime high32°C / 90°F🔥 sweltering
Nighttime low21°C / 70°F
Feels like (high)37°C / 99°F
Rainfall159 mm / 6.2 in⛈ soaked
Rainy days13 days
Humidity73%💧 humid
Dew point21°C / 69°F
Sunshine11.1 h/day
Daylight13.7 h
Wind13 km/h / 8 mph
Air quality (US AQI)34🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Foz do Iguaçu in December

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

BusySummer holidays in Brazil, school holidays in 3 of the markets that fill it(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Foz do Iguaçu's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Toughest weatherFoz do Iguaçu's weather peaks June–August, best around July.

December coincides with Devil's Throat walkway shut.

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Best weatherFair weatherToughest weather

What's on in Foz do Iguaçu in December

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Rule

    Timed park tickets, booked online

    1 Jan – 31 DecBook early

    Both sides sell entry by day and hour online and the Brazilian park caps arrivals per hour, so turning up without a slot in high season means waiting or missing it. Two countries, two tickets. Source ↗

  • Season

    Falls at their fullest

    1 Nov – 31 Mar · usuallyHigh water

    Rain over the whole upper basin reaches the falls with a lag, and flow is usually heaviest from November to March, around February at its peak. Expect spray, a soaked camera and a lot of noise.

  • Hazard

    Devil's Throat walkway shut

    1 Nov – 30 Apr · usuallyFlood seasonClosures

    When the Iguacu runs above the safe limit the catwalk out to the Devil's Throat closes on both sides, sometimes for days. The rest of the circuit stays open and the falls are, if anything, better. Source ↗

What's on around the world in December →

Where is Foz do Iguaçu?

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Foz do Iguaçu in December — FAQ

Is December a good time to visit Foz do Iguaçu?
December in Foz do Iguaçu: sweltering, soaked, with clean air — a gamble, with 13 rainy days. It ranks #10 of 12 months for Foz do Iguaçu on SeasonMap's comfort score (55/100).
What is the weather like in Foz do Iguaçu in December?
In December, Foz do Iguaçu averages a daily high of 32.2°C and a low of 21.1°C, with about 158.6 mm of rain over roughly 13.2 rainy days.
What is the air quality in Foz do Iguaçu in December?
Foz do Iguaçu has a mean US Air Quality Index of about 34 in December.