Climate averages 1991–2020
Buenos Aires weather
in September.
A mild, moderately wet month: the 8th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Buenos Aires: daytime highs average 17.3°C and nights cool to about 10.4°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 80 mm of rain on roughly 7 days, which makes September a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 51 min on an average September day.
The nearest other city in this atlas is Avellaneda (5 km away). In September its highs average 17.5°C, about as warm as Buenos Aires, with 74 mm of rain.
Among the 67 cities listed in Argentina, Buenos Aires ranks joint 55th of 67 for the warmest September highs and 57th of 67 for the driest September (rainfall, lowest first). The mean September high of those 67 cities is 19.4°C; Buenos Aires is 2.1°C cooler than that mean.
From September to October, average highs rise by 2.9°C to 20.2°C, and monthly rainfall rises from 80 mm to 119 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Buenos Aires climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 27.6°C20.3°C | 20.3°C | 83 | 6.9 | 14.214 h |
| February | 26.4°C19.7°C | 19.7°C | 99 | 8.1 | 13.413 h |
| March | 24.5°C18.1°C | 18.1°C | 96 | 7.6 | 12.312 h |
| April | 20.9°C14.6°C | 14.6°C | 102 | 8.1 | 11.211 h |
| May | 17.2°C11.5°C | 11.5°C | 72 | 6.8 | 10.310 h |
| June | 14.3°C8.6°C | 8.6°C | 74 | 7.7 | 9.910 h |
| July | 13.3°C7.5°C | 7.5°C | 74 | 7.1 | 10.110 h |
| August | 15.5°C8.8°C | 8.8°C | 71 | 6.6 | 10.811 h |
| September, selected | 17.3°C10.4°C | 10.4°C | 80 | 7.1 | 11.812 h |
| October | 20.2°C13.3°C | 13.3°C | 119 | 9.8 | 12.913 h |
| November | 23.4°C15.9°C | 15.9°C | 95 | 8.2 | 13.914 h |
| December | 26.3°C18.6°C | 18.6°C | 87 | 8.1 | 14.414 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Avellaneda in SeptemberArgentina · 5 kmHigh 17.5°C · Low 10.1°C · 74 mm rain
- Lomas de Zamora in SeptemberArgentina · 16 kmHigh 17.7°C · Low 9.6°C · 72 mm rain
- Quilmes in SeptemberArgentina · 16 kmHigh 17.4°C · Low 9.9°C · 74 mm rain
- Isidro Casanova in SeptemberArgentina · 22 kmHigh 18.2°C · Low 9.2°C · 72 mm rain
- Berazategui in SeptemberArgentina · 23 kmHigh 17.1°C · Low 10.3°C · 74 mm rain
- Laferrere in SeptemberArgentina · 24 kmHigh 18.3°C · Low 9.1°C · 72 mm rain
- Don Torcuato in SeptemberArgentina · 26 kmHigh 18.0°C · Low 9.8°C · 72 mm rain
- Bella Vista in SeptemberArgentina · 29 kmHigh 18.4°C · Low 9.2°C · 72 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Buenos Aires) is explained once on the Buenos Aires year overview and on the Sources, method and limits page.