September Weather in Busan, South Korea

Last updated: October 30, 2025

September in Busan, South Korea presents a delightful blend of warmth and humidity, with average temperatures hovering around 23°C (75°F), reaching a maximum of 29°C (84°F). As summer transitions to autumn, the city experiences 11 days of rain, contributing to a substantial 245 mm (9.6 in) of precipitation. With humidity levels at a balmy 80%, visitors can expect a tropical feel, making September an ideal time to enjoy Busan's vibrant culture and scenic coastlines, albeit with occasional rain showers to keep in mind.

September Temperature in Busan

In September, Busan welcomes a delightful transition from summer's heat, with temperatures averaging a comfortable 23°C (75°F) and reaching up to 29°C (84°F) during the day. The minimum temperature settles at a pleasant 17°C (63°F), making it a lovely time for outdoor activities and seaside visits. As the city shifts towards autumn, the warmth begins to recede, showcasing a trend of gradual cooling that contrasts sharply with the sweltering July and August months. This change not only provides respite but also enhances the vibrant scenery, as the playful summer atmosphere gives way to the crispness of fall, encouraging locals and visitors alike to explore Busan's stunning landscapes and cultural offerings.

September Weather in Busan: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Busan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Busan, September typically has an average temperature of 23°C (75°F), with highs reaching up to 29°C (84°F) and lows dropping to around 17°C (63°F).
JanFebMarAprMayJunJulAugSepOctNovDec424451566369768074665745
Data source: Temperature data for Busan generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Busan

In September, Busan experiences a significant uptick in precipitation, receiving 245 mm (9.6 inches) over 11 days, marking it as one of the wettest months of the year. This amount is comparable to the deluges of July but distinctive enough to signal the transition from summer to autumn. As summer's heat fades, the rainfall contributes to lush landscapes but also highlights the monsoon's lingering grip. While the earlier months of the year, such as January and February, showcase relatively mild precipitation levels around 38 mm (1.5 inches) and 46 mm (1.8 inches) respectively, September's abundance underscores a shift in weather patterns. This trend of increased moisture continues through the fall, with October seeing a sharp drop to 91 mm (3.6 inches), suggesting a gradual easing of the rainy season. Overall, September stands out as a dynamic month in Busan's annual climate cycle, merging the remnants of summer storms with the calm that precedes autumn.

September Precipitation Trends in Busan

The chart displays monthly precipitation patterns in Busan, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Busan, September typically receives around 245 mm (9.6 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec3946100114114167249158245912525
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Busan

In September, humidity in Busan, South Korea, averages a comfortable 80%, marking a slight decrease from the sweltering summer months of July and August, which peak at 95% and 93%, respectively. As the warm season transitions into autumn, the humidity begins to stabilize, reflecting a gradual trend towards drier conditions. This month serves as a bridge, transitioning from the heavy, moisture-laden air of summer, while still retaining some of the warmth and humidity that characterize the coastal region. Following September, humidity continues to decline through October and November, ultimately settling down to 75% by November, indicating the onset of cooler, more refreshing autumn weather.

September Average Humidity in Busan

This chart illustrates the average monthly humidity levels in Busan, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Busan is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec73%67%65%75%83%87%95%93%80%77%75%73%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Busan

In September, Busan's UV Index reaches a notable 10, categorizing it as very high and indicating a burn time of just 15 minutes for unprotected skin. This marks a slight decline from the extreme values of July and August, where the index peaked at 12, but still signifies a strong need for sun protection strategies as summer transitions into autumn. Overall, September's UV levels suggest that sun safety remains crucial, even as we approach the cooler months. For detailed UV trends and more information, check out Busan UV Index.

Maximum UV Index Levels in Busan for September

The chart shows the monthly maximum UV Index (UVI) for Busan in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Busan typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec457101011121210753
Data source: Busan September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Busan

September in Busan, South Korea, is marked by a delightful 241 hours of sunshine, making it a refreshing transition from the vibrant summer months. Following the sun-drenched days of July and August, which boast 266 and 290 hours respectively, September's sunshine begins to wane but still offers ample light and warmth for outdoor activities. As autumn sets in, the average hours of sunlight gradually decline, paving the way to October's slightly more muted 256 hours. This pattern highlights Busan's dynamic climate, where the lingering warmth of summer meets the crispness of fall, inviting both locals and visitors to soak up the last rays of summer before the cooler months approach.

Monthly Sunshine Duration in Busan: September Highlighted

The September sunshine duration represents the total number of hours Busan experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec196h239h267h278h295h293h266h290h241h256h238h244h
Data source: Busan September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Busan During September

As autumn begins to unfold in Busan, South Korea, September offers a transition marked by a 33% chance of sunny weather. This likelihood aligns with the summer months, where the sun’s presence wanes throughout June and July, both showing significantly lower odds of clear skies. Interestingly, September does not see a substantial recovery in sunshine compared to the preceding months, mirroring the uncertainty felt in August. However, as the city moves into October, a notable increase to 57% heralds the return of brighter days. The trend indicates a gradual enhancement in sunshine as the year progresses into fall, providing a promising outlook for those seeking clearer skies later in the season.

Percentage of Sunny Days in September in Busan

The chart illustrates the percentage of sunny days in Busan throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Busan experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec53%54%40%45%39%34%23%31%33%58%68%73%
Data source: Busan September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Busan in September

As September unfolds in Busan, South Korea, the city enjoys an average of 12 hours of daylight, marking a gentle decline from the summer's peak. This month serves as a transition, bridging the longer days of summer—where daylight stretches to 14 hours in June through August—and the shorter days that follow in the fall, with October dropping to 11 hours. The gradual decrease from the bright, bustling days of summer reflects a serene shift towards autumn, allowing for a beautiful blend of warm light and softening shadows as the city prepares for the cooler months ahead. This rhythmic ebb and flow of daylight not only highlights Busan’s vibrant seasonal changes but also invites residents and visitors alike to relish the unique charm each period brings.

Average Daylight Hours in Busan for September

The chart illustrates the variation in daylight duration in Busan throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 4m10h 54m11h 58m13h 4m14h14h 27m14h 13m13h 25m12h 22m11h 16m10h 18m9h 49m
Data source: Busan daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Busan

In September, the winds in Busan, South Korea pick up their pace again, averaging a brisk 6.7 m/s (15 mph), which nearly ties with the higher wind speeds of early winter. This month marks a noticeable increase compared to the lighter breezes of June and August, where winds lingered around 5.2 m/s (12 mph). As summer transitions into autumn, the gusts rejuvenate the coastal atmosphere and invigorate outdoor activities. Following a dip in the summer months, September's invigorating winds hint at the shifting seasons, creating a compelling backdrop for the city's vibrant street life. The winds only slightly taper off into October, suggesting that while summer's warmth may fade, the September winds remind us of the energetic spirit that continues to blow through this dynamic coastal city.

Average September Wind Speed in Busan

The chart displays monthly wind speed patterns in Busan, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec6.66.96.06.05.64.35.25.26.7 m/s5.15.86.3
Data source: Busan September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Busan Compares to Other Months

Weather in Busan varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Busan, focusing on differences in temperature, rainfall, humidity, and UV levels.

In September, the weather is warm and humid, with temperatures ranging from a minimum of 17°C (63°F) to a maximum of 29°C (84°F) and an average of 23°C (75°F). This month sees significant rainfall, totaling 245 mm (9.6 in) over about 11 days, contributing to a high humidity level of 80%. In contrast, January presents a starkly different climate with much colder temperatures, featuring a minimum of -7°C (20°F), an average of 6°C (43°F), and a maximum of 18°C (64°F). Precipitation is minimal during this month, totaling only 38 mm (1.5 in) over approximately 4 days, and the humidity is relatively lower at 72%. For more information on January weather specifics, you can visit Busan weather in January.

September and February present starkly contrasting weather patterns. In September, temperatures range from a mild 17°C (63°F) to a warm 29°C (84°F), with an average temperature of 23°C (75°F). This month is characterized by higher precipitation, totaling 245 mm (9.6 in) over 11 days, and an elevated humidity level of 80%. In contrast, February sees much cooler temperatures, with a minimum of -5°C (24°F) and a maximum of 16°C (61°F), averaging only 7°C (44°F). Precipitation is significantly lower at 46 mm (1.8 in) over 4 days, and humidity drops to 67%. For more insights, check out Busan weather in February.

September weather in Busan is characterized by warm temperatures, with averages ranging from a minimum of 17°C (63°F) to a maximum of 29°C (84°F). The month sees relatively high humidity at 80% and significant precipitation, totaling 245 mm (9.6 in) over 11 days. In contrast, March experiences much cooler conditions, with temperatures ranging from a minimum of 1°C (34°F) to a maximum of 16°C (62°F), and an overall average of 11°C (51°F). Precipitation in March is lower, at 100 mm (3.9 in) over 8 days, and the humidity is notably less, at 65%. For more detailed information on March weather, check Busan weather in March.

In comparing the weather between September and April, it's clear that September is significantly warmer and wetter. With average temperatures ranging from a minimum of 17°C (63°F) to a maximum of 29°C (84°F), September boasts a comfortable climate, albeit accompanied by higher humidity levels of around 80% and considerable rainfall totaling 245 mm (9.6 in) over 11 days. In contrast, April experiences cooler temperatures, with averages fluctuating between 6°C (42°F) and 19°C (66°F) and less frequent precipitation, amounting to 114 mm (4.5 in) over just 7 days. This results in a milder environment with lower humidity at 75%. For more details about the weather specifics in April, you can visit Busan weather in April.

In comparing the weather of September and May, September tends to be significantly warmer, with average temperatures ranging from a minimum of 17°C (63°F) to a maximum of 29°C (84°F), while May's temperatures are milder, with minimums of 10°C (50°F) and maximums of 22°C (71°F). Precipitation in September is notably higher, averaging 245 mm (9.6 in) over 11 days, compared to May's 113 mm (4.5 in) over just 7 days. Despite September's warmth, it also has a high humidity level of 80%, slightly lower than May's humidity at 83%. For more detailed information, you can check Busan weather in May.

September weather exhibits warmer temperatures compared to June, with average highs reaching up to 29°C (84°F) versus June's maximum of 25°C (78°F). The minimum temperatures are relatively similar, with September starting at 17°C (63°F) and June at 16°C (62°F). However, September experiences significantly higher precipitation, tallying 245 mm (9.6 in) over 11 days, compared to June's 167 mm (6.6 in) across 8 days. The humidity remains high in both months, with September at 80% and June slightly higher at 87%. For a detailed look at June weather in Busan, you can visit Busan weather in June.

In comparing the weather of September and July, September typically experiences slightly cooler temperatures, with a minimum of 17°C (63°F) and an average of 23°C (75°F), compared to July's minimum of 19°C (66°F) and average of 24°C (76°F). While both months see significant rainfall, September has a little less precipitation at 245 mm (9.6 in) over 11 days, compared to July's 249 mm (9.8 in) over 13 days. Additionally, September’s humidity averages 80%, offering a somewhat drier atmosphere than July's high humidity level of 95%. For more detailed insights into July's weather patterns, check out Busan weather in July.

In comparing the weather between August and September, it is clear that September experiences slightly cooler temperatures, with an average of 23°C (75°F) compared to August's warmer average of 27°C (81°F). August also boasts higher maximum temperatures, reaching up to 31°C (88°F), while September peaks at 29°C (84°F). However, September sees increased precipitation, averaging 245 mm (9.6 in) over 11 days, compared to August's 158 mm (6.2 in) over 13 days. Additionally, September has lower humidity levels at 80%, versus August's higher humidity at 93%. For a more detailed look at August weather, visit Busan weather in August.

In September, temperatures are generally warmer, with average highs reaching up to 29°C (84°F) and a relatively high humidity of 80%. However, this month also sees significant rainfall, totaling 245 mm (9.6 in) over 11 days. In contrast, October brings a notable drop in temperatures, with average highs of 26°C (78°F) and a minimum of 9°C (49°F). Precipitation decreases significantly to 91 mm (3.6 in) over just 5 days, and humidity slightly lowers to 77%. For a detailed look at the weather in this month, you can check Busan weather in October.

September and November present a striking contrast in weather conditions. In September, temperatures are significantly warmer, with a minimum of 17°C (63°F) and an average high reaching 29°C (84°F). However, this warmth comes with considerable rainfall, accumulating to 245 mm (9.6 in) over about 11 days, creating a humid environment with an average humidity of 80%. In contrast, November experiences much cooler temperatures, ranging from a minimum of 3°C (38°F) to a maximum of 21°C (70°F), with a lower average of 14°C (57°F). Additionally, November sees only 24 mm (1.0 in) of precipitation over just 3 days and a slight decrease in humidity at 75%. For more details on the weather specifics, you can check Busan weather in November.

September and December present strikingly different weather patterns. September enjoys a mild to warm climate with average temperatures ranging from a minimum of 17°C (63°F) to a maximum of 29°C (84°F), accompanied by significant rainfall of 245 mm (9.6 in) spread over 11 days and high humidity levels around 80%. In contrast, December ushers in a much colder atmosphere, characterized by a stark temperature drop, with averages between -4°C (25°F) and 18°C (64°F). Precipitation in December is minimal, totaling only 25 mm (1.0 in) over a mere 3 days, and the humidity decreases to 73%. For more details, you can check Busan weather in December.

Compare Busan's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Busan

As summer transitions into autumn, September in Busan brings a delightful change in weather. While temperatures remain pleasantly warm, averaging around 23°C (75°F), the month is marked by higher humidity and significant rainfall, with 245 mm (9.6 in) spread across 11 days. This combination creates a lush, vibrant atmosphere, ideal for enjoying outdoor activities while appreciating the stunning coastal scenery. Compared to the sweltering heat of August, September's climate is more temperate and refreshing, making it a perfect time to explore the city's cultural offerings. For more information, check out the detailed insights on Busan Climate.