Rosario weather in September

September in Rosario: nice, a little rain, with clean air — one of the best months to visit.

Updated September 2026 · climate normals from ERA5 reanalysis

Rosario🇦🇷 Argentina · Pampas & Uruguay · City91
  1. 75Jan
  2. 77Feb
  3. 81Mar
  4. 84Apr
  5. 83May
  6. 81Jun
  7. 79Jul
  8. 85Aug
  9. 91Sep
  10. 91Oct
  11. 86Nov
  12. 81Dec

#1 of 12 months in Rosario · #194 of 1413 destinations to visit in September · comfort 91/100 (tier S)

Days
23°C
Nights
9°C
Wet days
5
Sun
9.5 h
Humidity
65%
Daylight
12 h
Rosario, Argentina
Photo: Franco Garcia · Pexels

Traveller notes on Rosario in September

Other months in Rosario

Forum posters specifically recommend March or April for visiting Rosario, describing the weather then as noticeably more comfortable than the hotter January-February stretch. Posters more broadly rate March and April as beautiful months for travel across Argentina generally, with April weather described as delightful. Posters consistently describe Rosario itself as a kind of mini Buenos Aires - chic, attractive, and centered on a scenic riverfront rambla worth strolling for its parks, river views and upscale apartment buildings. Posters generally rate two to three days as enough time to enjoy the city, with April's milder temperatures adding real appeal to that recommendation.
Tripadvisor community · April · 1 month ago · Read more on Tripadvisor ↗
Forum posters describe October as squarely inside Argentina's pleasant spring stretch - sunny, not too hot and not too wet, with the city's parks and gardens in full bloom. One recurring regional comparison posters make: Rosario runs noticeably more humid than nearby Cordoba, which is comparatively dry, though both cities get genuinely hot come summer. Posters recommend budgeting two to three days for Rosario itself, and specifically flag March/April and, by extension, the similarly mild October window as better timing than the peak-summer months of January/February when the heat becomes properly oppressive along the Parana riverfront.
Tripadvisor community · October · 1 month ago · Read more on Tripadvisor ↗

Add your own note from Rosario's card on the map.

Rosario climate normals — September

Daytime high23°C / 74°F😎 nice
Nighttime low9°C / 48°F
Feels like (high)22°C / 72°F
Rainfall39 mm / 1.5 in🌦 some rain
Rainy days5 days
Humidity65%💧 humid
Dew point8°C / 47°F
Sunshine9.5 h/day
Daylight11.9 h
Wind18 km/h / 11 mph
Air quality (US AQI)31🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Rosario in September

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Busyschool holidays in 2 of the markets that fill it, one of its best months for weather(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Rosario's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherRosario's weather doesn't swing hard through the year — comfort stays fairly steady in every month.

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What's on in Rosario in September

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Hazard

    Smoke off the delta

    15 Jul – 31 Oct · usuallySmoke season

    Burning on the wetland islands opposite has put the city under smoke for days at a stretch in dry years, worst when the wind sits in the east. It is a bad-year problem, not an every-year one. Source ↗

What's on around the world in September →

Nearby, and something's on

Within 300 km of Rosario — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Rosario?

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Rosario in September — FAQ

Is September a good time to visit Rosario?
September in Rosario: nice, a little rain, with clean air — one of the best months to visit. It ranks #1 of 12 months for Rosario on SeasonMap's comfort score (91/100).
What is the weather like in Rosario in September?
In September, Rosario averages a daily high of 23.1°C and a low of 8.7°C, with about 39 mm of rain over roughly 4.8 rainy days.
What is the air quality in Rosario in September?
Rosario has a mean US Air Quality Index of about 31 in September.

Within 300 km: Buenos Aires' Students' Day on 21 Sep.