Porto Alegre weather in December
December in Porto Alegre: hot, rainy, with clean air — a great time to visit.
Updated September 2026 · climate normals from ERA5 reanalysis
#9 of 12 months in Porto Alegre · #584 of 1413 destinations to visit in December · comfort 76/100 (tier B)
- Days
- 30°C
- Nights
- 20°C
- Wet days
- 11
- Sun
- 11.2 h
- Humidity
- 73%
- Daylight
- 14 h

Traveller notes on Porto Alegre in December
Other months in Porto Alegre
Forum posters generally rate October as one of Brazil's best weather months as spring gets underway, though real rain remains part of the seasonal transition. Posters describe Porto Alegre, in Brazil's far south, as running colder than most of the rest of the country, comparable to or cooler than Curitiba depending on the specific stretch of weather. Given the limited destination-specific detail available for October exactly, this note leans on that broader southern-Brazil pattern: expect mild, spring-like temperatures with a real chance of rain, cooler overall than the tropical conditions typical of Brazil's more northern cities. Posters generally rate October as a comfortable, moderate-temperature time to visit Porto Alegre, appropriate layers still worth packing.
Forum posters describe Rio Grande do Sul's climate as running genuinely cold in winter (0-18C in July/August) and hot in summer (up to 30C December-March), placing April into the autumn transition between those extremes - noticeably milder than deep summer but not yet into winter's chill. The nearby hill town of Gramado (a popular 2-3 hour day trip from Porto Alegre, known for its European-colonized, alpine-style architecture) is specifically called out as already turning cold by the September-October shoulder months given its higher elevation, a pattern posters say applies similarly heading into April from the other side of the year. Posters treat the shoulder-season months generally as a comfortable, less extreme alternative to visiting in the depths of either Porto Alegre's hot summer or cold winter.
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Porto Alegre climate normals — December
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Porto Alegre 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.
Peak crowdsChristmas and Réveillon, Summer holidays in Brazil, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Porto Alegre'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).
Fair weatherPorto Alegre's weather doesn't swing hard through the year — comfort stays fairly steady in every month.
What's on in Porto Alegre in December
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Holiday
Christmas and Réveillon
24 Dec – 1 JanChristmas & New YearClosuresCrowdedChristmas Day and New Year's Day are national holidays: many shops, restaurants and attractions close on both, a good share of residents leave town in the week between, and New Year's Eve, Réveillon, brings fireworks and crowds dressed in white. Source ↗
Where is Porto Alegre?
Porto Alegre in December — FAQ
- Is December a good time to visit Porto Alegre?
- December in Porto Alegre: hot, rainy, with clean air — a great time to visit. It ranks #9 of 12 months for Porto Alegre on SeasonMap's comfort score (76/100).
- What is the weather like in Porto Alegre in December?
- In December, Porto Alegre averages a daily high of 29.9°C and a low of 19.8°C, with about 111.4 mm of rain over roughly 10.7 rainy days.
- What is the air quality in Porto Alegre in December?
- Porto Alegre has a mean US Air Quality Index of about 39 in December.