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.

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For a detailed overview over the year and the best time to visit Brazil, check out our Porto Alegre's climate page.

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  

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

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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

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Historical weather 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.

Historical weather Temperatures Precipitation

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Porto Alegre historical weather extremes in September

According to our 22 years of weather records for Porto Alegre, the following extremes were recorded between 2003 and 2025.

• 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).

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.

Swimming

7/10

Camping

6/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Brazil, check out our Porto Alegre's climate page.

More climate data for Porto Alegre

Temperature Rainfall Sunshine Humidity Wind Speed

See the full Porto Alegre climate overview or explore weather in Brazil.