Rio de Janeiro weather in September
In September, Rio de Janeiro has an average high of 26 °C78 °F and an average low of 19 °C66 °F, with about 69 mm2.7 in of precipitation. It is the 9th warmest month of the year and ranks 9th for precipitation.
How September compares with other months
Compared with August, September is 0.7 °C1.3 °F warmer on average and wetter by 27 mm1.1 in. Compared with October, September is 1 °C1.7 °F cooler on average and drier by 39 mm1.5 in. Daylight lasts about 12.0 hours around the middle of the month. Average relative humidity is 77% and the average cloud amount 57%.
Is September a good time to visit Rio de Janeiro?
Yes — September is one of the most comfortable months to visit Rio de Janeiro by our comfort score, which favours average highs of 21–28 °C, lows above 5 °C, little rain and moderate humidity.
What to wear in September
For Rio de Janeiro in September, pack light summer clothes such as T-shirts, shorts or light dresses.
September in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| Rio de Janeiro | 2678 | 1966 | 692.7 |
| Nova Iguaçu | 2680 | 1865 | 722.8 |
| Maricá | 2678 | 1966 | 692.7 |
| Itaboraí | 3187 | 1763 | 612.4 |
| Queimados | 3289 | 1662 | 562.2 |
| Petrópolis | 2678 | 1254 | 612.4 |
| Araruama | 2678 | 1966 | 632.5 |
| Nova Friburgo | 2476 | 1254 | 602.4 |
| Volta Redonda | 3085 | 1660 | 562.2 |
Nearby places that are more than 1 °C1.8 °F warmer in September: Itaboraí and Queimados; cooler: Petrópolis and Nova Friburgo.
Other months in Rio de Janeiro
- January29 °C84 °F / 24 °C75 °F
- February29 °C84 °F / 24 °C75 °F
- March28 °C83 °F / 24 °C74 °F
- April27 °C81 °F / 22 °C72 °F
- May25 °C77 °F / 20 °C69 °F
- June25 °C77 °F / 19 °C66 °F
- July24 °C76 °F / 18 °C65 °F
- August25 °C77 °F / 18 °C65 °F
- September26 °C78 °F / 19 °C66 °F
- October26 °C80 °F / 20 °C68 °F
- November27 °C80 °F / 21 °C70 °F
- December28 °C82 °F / 23 °C73 °F
Frequently asked questions
How warm is Rio de Janeiro in September?
In September the average high in Rio de Janeiro is 26 °C (78 °F) and the average low is 19 °C (66 °F).
Does it rain a lot in Rio de Janeiro in September?
On average about 69 mm (2.7 in) of precipitation falls in September; it ranks 9th of the 12 months.
Is September the warmest month in Rio de Janeiro?
No. The warmest month in Rio de Janeiro is February, with an average high of 29 °C (84 °F). The coldest month is August, with an average low of 18 °C (65 °F).
How long is the day in Rio de Janeiro in September?
In the middle of September the day in Rio de Janeiro lasts about 12.0 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is Rio de Janeiro in September?
The average relative humidity in September is about 77%. Combined with warm days, it can feel muggy.
How cloudy is Rio de Janeiro in September?
On average about 57% of the sky is covered by cloud in September. This is the mean cloud amount from satellite data, not the number of sunny days.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 81 m, while Rio de Janeiro lies at about 12 m. Temperatures on this page were therefore adjusted by +0.4 °C0.8 °F using the standard lapse rate of 6.5 °C per 1,000 m.