Porto Alegre weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: February – December
What is the weather like in Porto Alegre in September?
In September, Porto Alegre is warm: daytime highs average 21 °C, and nights cool down to about 13 °C. The sea averages 17.3 °C – bracing, so a wetsuit helps for longer swims. Expect around 5 hours of sunshine a day. Rain is frequent, with about 11 rainy days and 158 mm in total. All in all, September is a good month for a holiday in Porto Alegre.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 73 | 71 | 71 |
| Day | 20° | 21° | 24° |
| Night | 11° | 13° | 15° |
| Sea | 16° | 17° | 20° |
| Sun | 5 h | 5 h | 6 h |
| Rain days | 10 | 11 | 12 |
More details for September
- Daylight
- 11 h 52 min06:24 – 18:16
- UV index
- 8 · very highclear sky, noon (estimate)All months
- Muggy days
- 3 daysdew point 18 °C or moreAll months
- Wind
- 18 km/haverage daily peakAll months
- Cloud cover
- 63 %on averageAll months
- Hot days
- 1 day30 °C or moreAll months
- Time zone
- UTC−3America/Sao_Paulo
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %33 %
- Few rainy daysweight 30 %47 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
- Rain jacket or umbrella
Porto Alegre in September: quick answers
Is Porto Alegre hot in September?
Warm rather than hot: in September, daytime highs in Porto Alegre average 21 °C and nights cool to about 13 °C. On about 1 days the thermometer climbs to 30 °C or more.
Can you swim in Porto Alegre in September?
Only if you don't mind cold water: in September the sea averages just 17.3 °C. Comfortable swimming is possible from November to April.
Does it rain much in Porto Alegre in September?
Rain is frequent, with about 11 rainy days and 158 mm in total.
Porto Alegre month by month
The whole year in Porto AlegreAll destinations: BrazilWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences