Weather in Rosario in September

Prime time. September is about as good as Rosario gets. Highs average 22 °C, lows 8.5 °C, and rain falls on 6 days — nothing in the month is working against you.

September ranks 2 of 12 in Rosario. Only August scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest September day reached 35.4 °C and the coldest night fell to -0.5 °C, and the wettest single day dropped 65 mm — roughly 112% of the month's rain in one day.

September is moderately variable: 10 mm in the driest year against 128 mm in the wettest, around an average of 58 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 8.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.

How September sits in the year

The month is on the way up: 3 °C warmer than August, and October adds another 3.5 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in September

11.8 hours of daylight, gaining 1 hours across the month. That is between Rosario's extremes of 14.3 and 10 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 27.9 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Rosario versus nearby

If Rosario is one option among several, the nearby comparison is worth making. Buenos Aires is the weaker option in September — 5.1 °C cooler, the same number of rain days. Córdoba is close enough to be a coin toss — 3.7 °C warmer, 2 days less rain.

So: September is effectively as good as it gets here — 1 points behind August, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Rosario

See all twelve months in Rosario, or where else to go in September.