Monthly climate guide
Rosario weather in September
Expect warm weather in Rosario in September: afternoons reach about 22°C (72°F), while nights drop to around 9°C (48°F). Around 56 mm of rain falls over the month (some rain), and skies are a mix of sun and cloud. Daytime highs are 3°C warmer than August and 3°C cooler than October.
What stands out in September
- Afternoons and nights feel like different seasons, roughly 14°C apart.
- Just 260 km apart, but Rosario runs about 2°C warmer than Merlo this month.
- In Rosario, September is early spring — the seasons are reversed south of the equator.
Avg high
22°C
72°F
Avg low
9°C
48°F
Rainfall
56 mm
some rain
Humidity
70%
relative
Sky
46%
cloud · a mix of sun and cloud
Rosario weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 33°C / 91°F | 19°C / 66°F | 125 mm | 61% | 47% |
| February | 31°C / 88°F | 18°C / 65°F | 143 mm | 67% | 53% |
| March | 28°C / 83°F | 15°C / 59°F | 105 mm | 69% | 42% |
| April | 25°C / 76°F | 13°C / 55°F | 116 mm | 75% | 49% |
| May | 20°C / 68°F | 10°C / 49°F | 67 mm | 81% | 56% |
| June | 17°C / 63°F | 6°C / 42°F | 24 mm | 79% | 49% |
| July | 16°C / 61°F | 5°C / 41°F | 26 mm | 78% | 53% |
| August | 19°C / 67°F | 7°C / 44°F | 42 mm | 74% | 44% |
| September | 22°C / 72°F | 9°C / 48°F | 56 mm | 70% | 46% |
| October | 25°C / 77°F | 12°C / 53°F | 133 mm | 69% | 53% |
| November | 29°C / 84°F | 15°C / 59°F | 119 mm | 64% | 45% |
| December | 32°C / 89°F | 17°C / 63°F | 128 mm | 59% | 46% |
What to pack for September
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
- An extra layer — evenings are noticeably cooler than afternoons
- A small travel umbrella, just in case
Is September a good time to visit Rosario?
Compare the months in the chart above to find your ideal window.
Best time to visit Rosario →Other Argentina cities in September
Cite or embed this data
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Rosario weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/argentina/rosario/september
<a href="https://weathercompare.eu/weather/argentina/rosario/september">Rosario weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/argentina/rosario" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="Rosario weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/argentina/rosario/september">Rosario weather in September</a> – WeatherCompare</p>
Rosario in September: quick answers
Is September a good time to visit Rosario?
September is a reasonable time for Rosario: highs around 22°C and about 56 mm of rain, though not one of the three best months.
How warm is Rosario in September?
Average highs are about 22°C (72°F) and average lows about 9°C (48°F), based on 10 years of daily data.
Does it rain a lot in Rosario in September?
Rosario typically gets around 56 mm of rain in September — some rain.
Figures are long-term averages for the area around Rosario (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.