Buenos Aires weather in September
In September, Buenos Aires has an average high of 17 °C62 °F and an average low of 12 °C53 °F, with about 83 mm3.3 in of precipitation. It is the 9th warmest month of the year and ranks 8th for precipitation.
How September compares with other months
Compared with August, September is 1.9 °C3.3 °F warmer on average and wetter by 12 mm0.5 in. Compared with October, September is 3 °C5.4 °F cooler on average and drier by 27 mm1.0 in. Daylight lasts about 11.9 hours around the middle of the month. Average relative humidity is 78% and the average cloud amount 53%.
Is September a good time to visit Buenos Aires?
September is not among the most comfortable months by our comfort score: it is cool (average high 17 °C62 °F) and it is fairly wet (83 mm3.3 in). The most comfortable months in Buenos Aires are November–January and April.
What to wear in September
For Buenos Aires in September, pack long sleeves, a sweater and a medium jacket.
September in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| Buenos Aires | 1762 | 1253 | 833.3 |
| Berazategui | 1865 | 846 | 763.0 |
| Laferrere | 1966 | 744 | 753.0 |
| Merlo | 1967 | 745 | 803.2 |
| La Plata | 1864 | 846 | 763.0 |
| Montevideo | 1560 | 1051 | 963.8 |
| San Nicolás de los Arroyos | 2169 | 745 | 752.9 |
| Rosario | 2271 | 847 | 582.3 |
| Tandil | 1661 | 439 | 612.4 |
Nearby places that are more than 1 °C1.8 °F cooler: Berazategui, Laferrere, La Plata and Montevideo.
Other months in Buenos Aires
- January28 °C82 °F / 22 °C71 °F
- February27 °C80 °F / 21 °C70 °F
- March25 °C76 °F / 19 °C67 °F
- April21 °C70 °F / 16 °C61 °F
- May17 °C63 °F / 13 °C55 °F
- June14 °C58 °F / 10 °C50 °F
- July13 °C56 °F / 9 °C48 °F
- August15 °C59 °F / 10 °C50 °F
- September17 °C62 °F / 12 °C53 °F
- October20 °C68 °F / 14 °C58 °F
- November23 °C74 °F / 17 °C63 °F
- December26 °C79 °F / 20 °C68 °F
Frequently asked questions
How warm is Buenos Aires in September?
In September the average high in Buenos Aires is 17 °C (62 °F) and the average low is 12 °C (53 °F).
Does it rain a lot in Buenos Aires in September?
On average about 83 mm (3.3 in) of precipitation falls in September; it ranks 8th of the 12 months.
Is September the warmest month in Buenos Aires?
No. The warmest month in Buenos Aires is January, with an average high of 28 °C (82 °F). The coldest month is July, with an average low of 9 °C (48 °F).
How long is the day in Buenos Aires in September?
In the middle of September the day in Buenos Aires lasts about 11.9 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is Buenos Aires in September?
The average relative humidity in September is about 78%. This is a long-term average for the whole day.
How cloudy is Buenos Aires in September?
On average about 53% 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.