Weather in Buenos Aires 🇦🇷
Monthly weather averages & travel planning
September
Avg Temp
17°C
Rain Days
7 days
Sun Hours
9 hrs
Humidity
70%
South America › 🇦🇷 Argentina › Buenos Aires
Updated: March 2026
Is September a Good Time to Visit Buenos Aires?
7/10
Good
September is a good time to visit Buenos Aires (7/10). With 9 daily sunshine hours and only 7 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 8th sunniest of the year in Buenos Aires. Culture-focused travellers and those who prefer lighter crowds will find September a practical choice, with prices running lower than peak January without sacrificing all the good weather. October offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Buenos Aires's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
vs August:16°C avg high
Based on 30-year climate normals (1991 to 2020), September in Buenos Aires averages 17°C by day and 11°C overnight, a range that places it in the temperate middle ground of the year. The month records approximately 9 sunshine hours per day and 79mm of total rainfall across 7 wet days, giving it a sunshine-to-rain ratio that is decidedly favourable for outdoor travel.
17°C
63°F
Avg High
11°C
52°F
Avg Low
7 days
79 mm total
Rain Days
9h
per day avg
Sunshine
70%
Moderate
Humidity
Temperature in Buenos Aires in September
The 6°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. Humidity averages 70%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 24 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 63°F average high, 52°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature Trends
High
Low
Rainfall (mm)
0-20 mm21-50 mm51-100 mm100+ mm
What to Wear in Buenos Aires in September
Morning11°CBefore the day warms up
Afternoon17°CPeak daytime temperature
Evening14°CAfter sunset cools down
Packing for Buenos Aires in September means dressing for 17°C days and 11°C evenings. A mid-weight jacket over a sweater handles 17°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 11°C, a modest 6°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues.
Local tip: Layers are more practical than a single heavy garment in Buenos Aires. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
Events in Buenos Aires in September
September has no major festivals or public holidays in Buenos Aires, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
What to Pack for Buenos Aires in September
Based on 17°C average highs and 7 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Buenos Aires in September
- Explore the old town's cobblestone backstreetsMorning (9-11am)At 17°C, conditions are pleasant for unhurried exploration on foot
- Visit hilltop viewpoints for panoramic city viewsLate afternoon (4-6pm)Low sun angle creates dramatic light for photography while temperatures remain comfortable
- Bicycle rental for a half-day city circuitMid-morning startMild 17°C temperatures are ideal for extended cycling without excessive effort
- Boat tour of the river, bay, or canal networkLate morning departureComfortable weather makes open-deck boats viable without wind-chill concerns
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningSeptember brings distinct seasonal changes to public green spaces worth exploring
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmSeptember seasonal produce is at peak availability, offering dishes not found at other times of year
Why is Buenos Aires mild in September?
September marks the transition into warmer conditions in Buenos Aires, as the sun angle climbs and day length extends. Temperatures averaging 17°C by day and 11°C overnight reflect a city shaking off winter: the morning air still carries a cool edge, but afternoons are noticeably warmer than even four weeks prior. At 35 degrees south latitude, spring is one of the most dynamic periods in the annual cycle, with weekly temperature changes that can be larger than the month-to-month shifts of summer. This volatility is part of the appeal: Buenos Aires in September has a freshness and energy that peak-summer heat tends to mute. Layers remain essential, but there are reliable pockets of warmth that reward patience. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Frequently Asked Questions
Buenos Aires in September
In September, Buenos Aires experiences average highs of 17°C (63°F) and lows of 11°C (52°F). Expect around 7 rainy days and 9 hours of sunshine per day, with humidity averaging 70%. The 6°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an overshirt or cardigan handles the cooler evenings. UV index averages 6, so sun protection is advisable on clear days.
Buenos Aires typically sees 7 rainy days in September, with total precipitation of around 79mm. This makes September one of the drier months of the year, and a reliable window for outdoor sightseeing and day trips. Rain showers tend to be brief when they do occur. For context, the driest month in Buenos Aires typically sees 4-6 fewer rain days than September.
Pack a warm jacket, sweaters, and layering pieces for Buenos Aires in September. Temperatures can drop to 11°C at night, so thermal underlayers are advisable for evening outings. Waterproof footwear is a sensible precaution even though rain days are limited. A scarf, hat, and gloves handle the windchill on clear cold days, which often feel colder than the thermometer reads.
Yes, September is an excellent time to visit Buenos Aires. With 9 daily sunshine hours and only 7 rainy days, conditions are ideal for sightseeing and outdoor activities. Temperatures averaging 17°C during the day are comfortable for long walks and outdoor dining. This is peak travel season, so booking accommodation in advance and arriving at popular attractions early in the morning helps avoid the busiest periods.
The average high temperature in Buenos Aires in September is 17°C (63°F), and the average low is 11°C (52°F). The mean daily temperature is approximately 14°C (57°F). The day-to-night range of 6°C is moderate, meaning a single light jacket covers most situations. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Buenos Aires is generally January. January offers the most sunshine at 12 hours per day and only 7 rainy days. Average temperatures reach 28°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around January gives you the best chance of dry, bright weather.
September is shoulder or low season in Buenos Aires, meaning fewer tourists and generally lower prices than peak months. With 9 sunshine hours and 7 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In September, Buenos Aires suits a range of activities thanks to cool conditions around 17°C. With few rainy days, outdoor activities are highly recommended. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 9 hours of sunshine, parks and waterfront walks are particularly enjoyable.
September ranks 8th sunniest of the year in Buenos Aires, with an average 9 daily sunshine hours. The driest months are January, May, and June. January is the hottest month (28°C avg high); July is the coolest (13°C). From here, temperatures rise 3°C into October. Compared to last month (August: 16°C high, 7 rain days), September is warmer and equally dry. September sits in the middle of the annual sunshine ranking for Buenos Aires, offering a reasonable balance of good weather and manageable crowds.
Year-Round Climate
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 28°C | 20°C | 7 | 12h | View |
| February | 27°C | 20°C | 8 | 11h | View |
| March | 25°C | 18°C | 8 | 10h | View |
| April | 21°C | 15°C | 8 | 9h | View |
| May | 17°C | 12°C | 7 | 8h | View |
| June | 14°C | 9°C | 7 | 7h | View |
| July | 13°C | 8°C | 7 | 7h | View |
| August | 16°C | 9°C | 7 | 8h | View |
| September | 17°C | 11°C | 7 | 9h | View |
| October | 20°C | 13°C | 10 | 10h | View |
| November | 24°C | 16°C | 8 | 11h | View |
| December | 27°C | 19°C | 8 | 12h | View |
January
7 rain days, 12h sun
28°20°
February
8 rain days, 11h sun
27°20°
March
8 rain days, 10h sun
25°18°
April
8 rain days, 9h sun
21°15°
May
7 rain days, 8h sun
17°12°
June
7 rain days, 7h sun
14°9°
July
7 rain days, 7h sun
13°8°
August
7 rain days, 8h sun
16°9°
September
7 rain days, 9h sun
17°11°
October
10 rain days, 10h sun
20°13°
November
8 rain days, 11h sun
24°16°
December
8 rain days, 12h sun
27°19°
Other Months in Buenos Aires
Plan Your Trip to Buenos Aires
Data Sources for Buenos Aires
Climate normals represent 30-year averages (1991-2020). Individual years may vary.