Last updated: August 21, 2025
Discover the September weather in Buenos Aires, Argentina, where the transition to spring brings a delightful mix of temperatures. Experience maximum highs of 27°C (81°F) during the day, tempered by an average of 15°C (59°F), while the nights can dip as low as 3°C (38°F). This month typically sees about 86 mm (3.4 in) of rain spread over 6 days, contributing to an overall humidity level of 72%. As the city awakens with blooming landscapes, September invites you to enjoy its mild climate and refreshing rains.
In September, Buenos Aires begins to shake off the winter chill, with temperatures gradually warming up as spring arrives. Minimums hover around a mild 3°C (38°F), while the average rises to a comfortable 15°C (59°F), and highs reach a pleasant 27°C (81°F). This transitional month marks a noticeable uptick in warmth compared to the preceding winter, invigorating the city’s vibrant parks and outdoor cafés. As the days lengthen and the air warms, it's a delightful time to explore the lively streets and indulge in the rich cultural offerings of Argentina's capital.
September marks a notable transition in Buenos Aires, as the city experiences a significant uptick in precipitation, with 86 mm (3.4 in) of rainfall over 6 days. This increase not only sets the stage for the wetter months ahead but also contrasts sharply with the relatively dry conditions of August, which recorded just 51 mm (2.0 in). The month heralds the onset of spring, bringing a refreshing shift in weather patterns that generally persist through October, when rainfall peaks at 103 mm (4.1 in). Overall, September's precipitation establishes it as a pivotal month, bridging the dry winter phase and the forthcoming exuberance of spring rains that help nourish the city’s vibrant landscapes.
As the seasons transition in Buenos Aires, September brings a moderate humidity level of 72%, a slight dip from the peak of 85% in May. This month serves as a transition point, showcasing a gradual decrease in humidity from April's high while still maintaining a considerable level of moisture in the air. Following the July and August months, which hover around the mid-60s, September marks a rise from August's 66%, indicating the approach of spring. Overall, the city's humidity levels demonstrate a clear trend of increasing moisture throughout late summer into early fall, creating an environment that is both refreshing and vibrant as nature prepares to bloom.
In September, Buenos Aires experiences a notable shift in the UV Index, which climbs to 8, categorized as very high. This change signals the onset of spring, as residents can expect a burn time of just 15 minutes under the sun. Following the more moderate UV levels of winter, September's index indicates a significant increase in solar intensity compared to the summer months, such as January and February, when the indices peak at 14. As the sun's rays become stronger, it's essential for both locals and visitors to remain vigilant and take precautions against sun exposure. For more detailed forecasts and tips on sun safety, check out Buenos Aires UV Index.
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As September arrives in Buenos Aires, the city basks in a pleasant 256 hours of sunshine, signaling the transition from the cool winter months to the warmth of spring. This slight dip from August’s 263 hours showcases a typical pattern where sunlight begins to soften before ramping up in October, which averages 301 hours. The trend reflects a gradual increase in daylight hours as spring unfolds, encouraging locals and visitors alike to emerge from the chilly winter and embrace outdoor activities. September sunshine invites blooming jacarandas and vibrant street life, setting the stage for a lively Argentine spring.
As we transition into September in Buenos Aires, the likelihood of sunny weather dips to 42%, marking a notable decline compared to the sunnier months of January and February, both at 60%. Following a string of brighter days in winter, this early spring month suggests a mix of cloudier skies and potential rain. However, as October approaches, the sun's return seems promising, with a significant rebound to 69% expected. This trend underscores the dynamic nature of Buenos Aires' weather, where the shift from winter to spring can bring about unpredictable conditions but ultimately hints at sunnier days ahead.
As September rolls around in Buenos Aires, daylight begins to extend again after the winter months, offering approximately 11 hours of light each day. This gradual shift from shorter days to longer ones mirrors the city's transition into spring, where residents can enjoy more time outdoors. Following September, October sees a further increase to 12 hours, and by the end of the year, daylight peaks at an impressive 14 hours in January. Overall, the trend showcases a rhythmic cycle of daylight that not only marks the changing seasons but also enriches the vibrant energy of the city throughout the year.
As September arrives in Buenos Aires, the city experiences a noticeable shift in its breezy ambiance. With an average wind speed of 5.4 m/s (12 mph), September marks the transition into spring, bringing with it a fresh burst of energy. This uptick in wind speeds is a contrast to the quieter gusts of August, which averaged only 3.9 m/s (9 mph). The increase reflects the seasonal awakening, setting the stage for more dynamic weather patterns ahead. Following September, the winds remain relatively strong through November, hinting at a playful flirtation between the refreshing spring air and the remnants of winter's chill. This invigorating trend makes September a captivating time for locals and visitors alike to embrace the outdoors in this vibrant city.
Weather in Buenos Aires varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Buenos Aires, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather in Buenos Aires offers a more moderate temperature range, with daily averages around 15°C (59°F) and maximums reaching up to 27°C (81°F). This month also sees higher humidity levels at 72% and more precipitation, averaging 86 mm (3.4 in) over about six days. In contrast, January experiences much warmer temperatures, with averages of 25°C (77°F) and highs soaring to 37°C (99°F). Despite the higher temperatures, January has lower humidity at 50% and less rainfall, totaling 59 mm (2.3 in) over the same six days. For more details, check out Buenos Aires weather in January.
When comparing the weather in September and February, distinct differences emerge. September experiences a more moderate temperature range, with minimums averaging around 3°C (38°F) and maximums reaching up to 27°C (81°F). In contrast, February boasts much warmer conditions, featuring minimum temperatures of 13°C (55°F) and maximums soaring to 33°C (92°F). Additionally, September receives more rainfall, totaling 86 mm (3.4 in) over six days, whereas February has slightly less precipitation at 72 mm (2.9 in) across eight days. The humidity also varies, with September being more humid at 72% compared to February's 61%. For more detailed insights, you can check Buenos Aires weather in February.
September and March present notably different weather conditions. In September, temperatures range from a chilly 3°C (38°F) at night to a comfortable 27°C (81°F) during the day, with an average of 15°C (59°F). The month sees about 86 mm (3.4 in) of precipitation over 6 days, accompanied by relatively high humidity at 72%. Conversely, March tends to be warmer with temperatures starting at a minimum of 10°C (51°F) and peaking at 32°C (89°F), averaging around 22°C (71°F). Although March has slightly less rainfall at 77 mm (3.0 in) spread over 8 days, the humidity is lower at 66%. For a detailed overview, you can check out Buenos Aires weather in March.
When comparing the weather in September and April, we find some notable differences. September typically experiences cooler temperatures, with a minimum of 3°C (38°F) and an average of 15°C (59°F), while April features milder weather with a minimum of 6°C (44°F) and an average of 19°C (66°F). Both months see relatively similar levels of precipitation—September receiving 86 mm (3.4 in) over about 6 days and April slightly less with 82 mm (3.2 in) over 8 days. However, April tends to be more humid, with a humidity level of 80% compared to September's 72%. This shift in temperatures and humidity levels makes April feel warmer and a bit more tropical. For more detailed information, check out Buenos Aires weather in April.
In comparing the weather between September and May, we find both months have similar average temperatures, sitting at around 15°C (59°F). September features a broader temperature range, with minimums dipping to 3°C (38°F) and maximums reaching up to 27°C (81°F). In contrast, May has slightly warmer minimum temperatures of 4°C (39°F) and a lower maximum of 25°C (77°F). Precipitation levels are similar as well, with September receiving 86 mm (3.4 in) over 6 days and May slightly less at 80 mm (3.2 in) over 7 days. Notably, May experiences higher humidity at 85%, compared to September's 72%. For more specific details on May's weather, you can visit Buenos Aires weather in May.
When comparing the weather in September and June, it's clear that September enjoys slightly warmer temperatures overall, with minimums of 3°C compared to June's 1°C. The average temperature in September is also higher at 15°C, while June's average is 12°C. However, June experiences a greater frequency of precipitation, with rain occurring on 8 days as opposed to 6 days in September, although the total precipitation is higher in September at 86 mm compared to June's 66 mm. Additionally, June has a slightly higher humidity level at 80% relative to September's 72%. For more detailed information on June weather, you can check Buenos Aires weather in June.
In comparing the weather between September and July, September features a wider temperature range, with minimums of 3°C (38°F) and maximums of 27°C (81°F), leading to an average temperature of 15°C (59°F). In contrast, July's temperatures are cooler, with minimums dipping to 1°C (34°F) and maximums reaching only 23°C (74°F), resulting in a lower average of 11°C (52°F). Precipitation in September is slightly higher at 86 mm (3.4 in) over 6 days, compared to July's 75 mm (3.0 in) over 8 days. Humidity levels are also marginally higher in September at 72%, while July holds a humidity level of 69%. For more detailed information, you can refer to this link: Buenos Aires weather in July.
In comparing the weather between September and August, we observe a notable increase in temperature and humidity. September experiences a minimum temperature of 3°C (38°F), an average of 15°C (59°F), and a maximum of 27°C (81°F), while August records slightly cooler temperatures with a minimum of 2°C (36°F), an average of 12°C (55°F), and a maximum of 24°C (75°F). Additionally, September sees 86 mm (3.4 in) of precipitation over 6 days, compared to August's 51 mm (2.0 in) over 5 days. This reflects a shift towards a more humid atmosphere in September, with humidity levels rising to 72% from August's 66%. For further details on August's climate, you can visit Buenos Aires weather in August.
September ushered in a transition from summer to fall, with temperatures ranging from a cool 3°C (38°F) at night to a comfortable 27°C (81°F) during the day, averaging around 15°C (59°F). While the month saw a total precipitation of 86 mm (3.4 in) over just 6 days, the humidity remained relatively high at 72%, contributing to a muggy atmosphere.
In contrast, October experiences warmer nights with a minimum temperature of 7°C (45°F) and daytime highs reaching up to 30°C (87°F), culminating in an average of 17°C (63°F). However, the month is slightly wetter, with precipitation increasing to 103 mm (4.1 in) spread over 10 days, though the humidity drops to a more comfortable 63%. For more detailed information, check out Buenos Aires weather in October.
September and November showcase notable differences in weather, reflecting the transition from early spring to the onset of summer. In September, temperatures fluctuate from a chilly minimum of 3°C (38°F) to a pleasant average of 15°C (59°F), peaking at a warm 27°C (81°F). The month experiences a total precipitation of 86 mm (3.4 in) over six days, accompanied by a higher humidity level of 72%.
In contrast, November boasts milder temperatures, beginning at a minimum of 9°C (49°F) and averaging 21°C (69°F), with a maximum reaching a striking 33°C (91°F). This month sees slightly less precipitation at 77 mm (3.0 in), although rain occurs over eight days, and the humidity drops to a more comfortable 59%. For more detailed insights into the weather during this month, check out Buenos Aires weather in November.
The weather in September is generally cooler and more variable compared to December, presenting a minimum temperature of 3°C (38°F) and an average of 15°C (59°F), while December boasts a milder minimum of 10°C (50°F) and a significantly warmer average of 23°C (73°F). Additionally, September experiences higher humidity at 72% and more precipitation, totaling 86 mm (3.4 in) over 6 days, whereas December has less precipitation at 66 mm (2.6 in) over 7 days and a reduced humidity of 56%. For more information on December's weather, you can check Buenos Aires weather in December.
As the vibrant city of Buenos Aires transitions into spring, September showcases a unique blend of mild temperatures and occasional rainfall. With average daily highs hovering comfortably around 15°C, the days are pleasantly warm, contrasting sharply with the cooler nights that can dip to around 3°C. Unlike the heavy downpours of summer, September experiences modest precipitation, typically spanning just a few days, allowing for plenty of dry moments to explore the city's charm. The humidity of 72% adds a refreshing touch to the air, making outdoor activities enjoyable. For those looking to understand more about the city's climate throughout the year, visit Buenos Aires Climate for a deeper dive into what each month holds.