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Porto Alegre Weather in September
Porto Alegre in September sees high daytime temperatures of 23°C (73°F) and nighttime lows of 13°C (55°F). Rainfall is fairly high this month at around 155 mm (6.1 in), so pack a rain jacket to stay dry.
Rainfall in Porto Alegre in September
Typically, about 18 days will experience rainfall, with an average of 155 mm (6.1 in) for the month. Expect frequent rainfall this month, and not just light drizzle. When it rains, it tends to come down hard.
Temperature in Porto Alegre in September
Porto Alegre in September gets highs of 23°C (73°F) during the day and drops to 13°C (55°F) at night. Overall, the month follows a fairly predictable daily temperature pattern. Nights drop to around 13°C (55°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.
Sunshine in Porto Alegre in September
You can expect a moderate amount of sunlight, with approximately 145 hours. This means a pleasant mix of sun and overcast.
Wind Speed in Porto Alegre in September
Average wind conditions reach 1 m/s (2 knots) in September. This creates generally peaceful weather with subtle air movement. Remember this is an average: some days are windless while others have noticeable or very gentle breezes.If you're a fan of comfortable temperatures and drier conditions, September is a great time to visit.
Porto Alegre Temperature in September
Min Temperature
13°C (55°F)
Max Temperature
23°C (73°F)
Chance of Rain
60%
Precipitation
155 mm (6.1 in)
Rainy days
18 days
Humidity
78%
Windspeed
1 m/s (2 knots)
Sunshine
145 hours
Percentage Sunshine
Porto Alegre Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Porto Alegre - and find the best time to visit.
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in Porto Alegre typically stay consistent throughout September, with daily highs averaging around 23°C (73°F). Nights are cool, with lows typically ranging from 12°C (54°F) to 15°C (59°F).
Average temperatures in September
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather records for Porto Alegre in September
Browse day-by-day weather records for Porto Alegre spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Porto Alegre historical weather extremes in September
According to our 23 years of weather records for Porto Alegre, the following extremes were recorded between 2003 and 2026.
- Porto Alegre recorded its highest September temperature of 36°C (97°F) on September 6, 2004.
- On September 5, 2008, Porto Alegre saw its coldest September day with temperatures maxing out at 12°C (54°F).
- The coldest night in September in Porto Alegre was on September 6, 2006, with a minimum of 3°C (37°F).
- The wettest September day on record brought 70 mm (2.8 in) of precipitation to Porto Alegre (September 16, 2017).
Best Places in Brazil in September
Find out more about the weather in Brazil and which places have the best travel conditions in this month. See all of Brazil in September →
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
What to Wear in Porto Alegre in September
Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Heavy rain is guaranteed, please bring a good poncho and waterproof everything! Sunglasses could come in handy during the sunnier parts of your trip.
What To Do in Porto Alegre in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
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Swimming7/10 -
Camping6/10
Porto Alegre 3-Day Forecast
More climate data for Porto Alegre
Temperature Rainfall Sunshine Humidity Wind Speed
See the full Porto Alegre climate overview or explore weather in Brazil.
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