Last updated: October 30, 2025
Experience the vibrant September weather in Seongsu, South Korea, where daily temperatures can soar up to a maximum of 31°C (88°F), presenting a warm embrace with an average of 21°C (70°F). While the days are generally inviting, evenings can cool down to a refreshing 8°C (48°F). Rain is a frequent visitor this month, contributing to a total of 201 mm (7.9 in) over approximately 11 days, creating a lush atmosphere. With humidity levels around 80%, September in Seongsu offers a unique blend of warmth and moisture, perfect for those seeking to enjoy the vibrant fall season.
In September, Seongsu, South Korea, transitions into a season of milder temperatures, marking a significant shift from the summer heat. The minimum temperature settles at a cool 8°C (48°F), providing a refreshing respite compared to the sweltering highs of August. With an average of 21°C (70°F), it's an ideal time for outdoor activities, as the heat peaks at a pleasant 31°C (88°F), making it one of the more comfortable months of the year. As the leaves begin to change and the air turns crisp, September serves as a beautiful bridge from the warm summer days to the more temperate autumn season, inviting both locals and visitors to embrace the stunning scenery and vibrant atmosphere of this dynamic neighborhood.
In September, Seongsu experiences a significant precipitation total of 201 mm (7.9 in), making it one of the wetter months of the year. With rain falling on 11 days, this period marks a transition from the heavy summer rains, hinting at the tail end of the monsoon season. The precipitation levels are notably lower than the 261 mm (10.3 in) recorded in July and 214 mm (8.4 in) in August, yet they remain substantial, contributing to the city’s lush autumn landscape. This gradual decrease in rainfall sets the stage for October's much lighter totals, reflecting a broader trend of diminishing precipitation as the year progresses.
As summer transitions into autumn, September in Seongsu, South Korea experiences a noticeable decrease in humidity, settling at a comfortable 80%. This slight drop follows the sweltering highs of July and August, which boast humidity levels around 95% and 93%, respectively. The shift from the peak summer months reflects the gradual cooling that begins in September, laying the groundwork for more temperate conditions in October and November, where humidity levels hover around 78% and 76%. The pattern showcases a dynamic range of humidity, peaking in the summer and retreating as the year winds down, offering a variety of experiences for residents and visitors alike.
As summer transitions to fall, September in Seongsu, South Korea, maintains a very high UV Index of 10, reminiscent of the peak intensity experienced in May and June. This level indicates a significant risk of harm from unprotected sun exposure, requiring a burn time of just 15 minutes. Following the extreme UV Index peaks of 12 in July and August, September still demands vigilance, as the sun's rays remain potent. While the UV Index naturally drops in October, the increasing strength from winter months ahead underscores a consistent need for sun protection throughout the year. For more detailed insights, check out the Seongsu UV Index.
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In Seongsu, South Korea, September reveals a blend of lingering summer warmth and the onset of autumn, showcasing 246 hours of sunshine. This month typically holds its own even as it follows the sun-drenched days of August, which boasted 286 hours of sunshine—one of the year's peaks. As summer transitions into fall, this noticeable dip reflects the gradual reduction in daylight hours, a trend seen as the year moves toward winter. Interestingly, the sunniest months, like May and June with 304 and 302 hours respectively, set the stage for a vibrant September, allowing the community to savor the fading warmth before welcoming the cooler October days ahead.
As summer transitions to autumn in Seongsu, South Korea, September offers a 34% chance of sunny weather. This marks a slight improvement from the peak of summer in July and August, which see considerably lower odds of sunshine at 21% and 28% respectively. However, the likelihood of clear skies remains relatively modest, overshadowed by the sunnier months of October and November, which enjoy chances of 51% and 56%. The patterns suggest that while September might still bring cloudy days, a hint of sun is more likely as the region heads towards the golden hues of fall.
As September rolls into Seongsu, South Korea, daylight begins to wane, offering about 12 hours of sunlight—slightly less than the 13 hours experienced in the peak of summer. This gradual shift marks a transition from the vibrant light of the warmer months towards the shorter days of fall and winter. Throughout the year, daylight duration typically increases from around 10 hours in January and February, reaching a summer high of 14 hours in June, July, and August. As the months progress, we see a consistent decline from August’s lingering brightness back down to 10 hours in November, culminating in the brief 9 hours of December. This cyclical pattern beautifully encapsulates the changing seasons, evoking a sense of rhythm and anticipation for the cooler months ahead.
As September arrives in Seongsu, South Korea, a gentle shift in the wind patterns can be felt, with an average wind speed of 2.4 m/s (5 mph). This marks a noticeable increase from the stillness of the summer months, where July and August saw the calmest breezes at just 1.9 m/s (4 mph). The transition into autumn brings a refreshing breath of air, reminiscent of the briskness that often accompanies the change of seasons. Looking ahead, October and November maintain a similar gentle flow, with averages returning to 2.0 m/s (5 mph) and 2.4 m/s (5 mph) respectively. This pattern not only highlights the soothing nature of September's winds but also sets the stage for the cool, invigorating days of fall to come.
Weather in Seongsu varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Seongsu, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January offer stark contrasts in weather. In September, temperatures range from a minimum of 8°C (48°F) to a maximum of 31°C (88°F), with an average of 21°C (70°F). The month sees a substantial 201 mm (7.9 in) of precipitation over approximately 11 days, accompanied by high humidity at 80%. In contrast, January presents a much colder climate, with temperatures dropping to a minimum of -19°C (-2°F) and peaking at 16°C (60°F), averaging around -1°C (31°F). Precipitation in January is considerably lower at 29 mm (1.1 in) across about 5 days, and humidity is also lower at 71%. For more details on the winter conditions, check out Seongsu weather in January.
September and February present striking contrasts in weather. In September, temperatures range from a mild 8°C (48°F) at night to a warm 31°C (88°F) during the day, with an average of 21°C (70°F). This month also sees significant rainfall, totaling 201 mm (7.9 in) over 11 days, and high humidity levels at 80%. In contrast, February experiences much colder conditions, with nighttime temperatures dropping to a frosty -14°C (7°F) and an average of just 1°C (34°F), peaking at 22°C (71°F). Precipitation is minimal in February, amounting to 39 mm (1.5 in) over only 5 days, and humidity is lower at 68%. For a closer look at the specifics of February weather in Seongsu, you can check Seongsu weather in February.
September and March present contrasting weather patterns, highlighting the transition between summer and spring. In September, temperatures range from a pleasant 21°C (70°F) on average to a warm 31°C (88°F) at its peak, while the minimum dips to 8°C (48°F). The month also sees significant rainfall, with 201 mm (7.9 in) over 11 days and humidity levels around 80%. In contrast, March experiences much cooler temperatures, with an average of 7°C (45°F), maxing out at 23°C (74°F) and a chilling minimum of -5°C (24°F). Precipitation is notably lower at 68 mm (2.7 in) across 8 days, accompanied by a reduced humidity of 67%. For more detailed information, you can check Seongsu weather in March.
September and April present contrasting weather patterns, highlighting the transition from late summer to spring. In September, temperatures can range from a chilly 8°C (48°F) at night to a warm 31°C (88°F) during the day, with an average of 21°C (70°F). The month is characterized by significant rainfall, totaling 201 mm (7.9 inches) over about 11 days, and a high humidity of 80%. In comparison, April offers cooler temperatures, with a minimum of -2°C (29°F), an average of 12°C (55°F), and a maximum of 28°C (83°F). Precipitation is much lighter in April, amounting to 63 mm (2.5 inches) over 7 days, accompanied by slightly lower humidity at 78%. For a more detailed look at the weather in April, you can visit Seongsu weather in April.
September and May offer distinct weather patterns, reflective of the transition periods in spring and autumn. September boasts a higher average temperature of 21°C (70°F), with a maximum reaching 31°C (88°F), while May's average is slightly cooler at 18°C (64°F), peaking at 30°C (86°F). However, September is notably wetter, receiving 201 mm (7.9 in) of precipitation over 11 days compared to May's 90 mm (3.5 in) over 9 days. Humidity levels are high in both months, with September at 80% and May at 85%, making both months feel quite warm and damp. For specific insights into May's climate, you can visit Seongsu weather in May.
September and June present distinct weather profiles. In September, temperatures range from a cool 8°C (48°F) at night to a warm average of 21°C (70°F) during the day, peaking at a hot 31°C (88°F). This month experiences considerable rainfall with 201 mm (7.9 in) of precipitation over 11 days, accompanied by a humidity level of 80%. Conversely, June is slightly milder overall, with minimum temperatures of 10°C (51°F), an average of 22°C (71°F), and maximums reaching 33°C (91°F). Rainfall in June is less abundant, totaling 131 mm (5.2 in) across 10 days, but humidity is higher at 87%. For a detailed overview of June weather, check out Seongsu weather in June.
In comparing the weather between September and July, it's clear that July is significantly warmer, with minimum temperatures averaging 17°C (62°F) and maximums reaching up to 35°C (95°F). In contrast, September experiences cooler temperatures with a minimum of 8°C (48°F) and a maximum of 31°C (88°F). Both months see a fair amount of rainfall, but July receives more precipitation overall, amounting to 261 mm (10.3 in) compared to September’s 201 mm (7.9 in) and has more rainy days, with 17 in July versus 11 in September. Humidity levels are also higher in July at 95% compared to 80% in September, contributing to a more oppressive summer feel. For more detailed July weather information, visit Seongsu weather in July.
In comparing the weather between August and September, notable differences emerge. In September, temperatures range from a cool minimum of 8°C (48°F) to a warm average of 21°C (70°F), peaking at a maximum of 31°C (88°F). This month experiences significant rainfall, with 201 mm (7.9 in) over 11 days, while humidity remains high at 80%. In contrast, August is warmer, with temperatures averaging 26°C (79°F) and reaching maximums of 37°C (99°F), and it sees slightly more precipitation of 214 mm (8.4 in) across 17 days, accompanied by a higher humidity level of 93%. For more detailed information, you can check Seongsu weather in August.
September and October present a noticeable shift in weather patterns. In September, temperatures see a minimum of 8°C (48°F) and an average of 21°C (70°F), peaking at a warm 31°C (88°F). The month is characterized by substantial rainfall, with 201 mm (7.9 in) of precipitation over 11 days, coupled with fairly high humidity at 80%. In contrast, October brings cooler temperatures, with a minimum of 0°C (32°F) and an average of 14°C (58°F), though it still reaches a maximum of 30°C (86°F). Precipitation decreases significantly to 67 mm (2.6 in) over just 5 days, while humidity slightly drops to 78%. For more details, check out Seongsu weather in October.
September and November showcase a stark contrast in weather patterns. In September, temperatures range from a pleasant minimum of 8°C (48°F) to a warm maximum of 31°C (88°F), while the average hovers around 21°C (70°F). The month is marked by significant rainfall, totaling 201 mm (7.9 in) over 11 days, coupled with high humidity at 80%. In contrast, November sees a notable drop in temperatures, with lows plunging to -4°C (26°F) and an average of only 8°C (46°F), though it maintains a maximum of 21°C (70°F). Precipitation decreases substantially to 42 mm (1.6 in) over just 6 days, and humidity dips slightly to 76%. For more information, you can check Seongsu weather in November.
September typically showcases a warm and pleasant climate, with average temperatures around 21°C (70°F) and maximums reaching up to 31°C (88°F). However, it also experiences considerable rainfall, with 201 mm (7.9 in) of precipitation spread over 11 days, and humidity levels hovering around 80%. In contrast, December brings a stark change as temperatures dip significantly, averaging just 1°C (34°F), with minimums plummeting to -13°C (8°F). The month sees much less precipitation, totaling only 31 mm (1.2 in) across 5 days, and lower humidity at 73%. For more detailed weather insights, you can refer to Seongsu weather in December.
As September unfolds in Seongsu, the weather brings a noticeable shift from the sweltering summer months. With average temperatures settling around 21°C (70°F), the crisp air is a refreshing change, making outdoor activities all the more enjoyable. However, the month is marked by considerable rainfall, with about 201 mm (7.9 in) of precipitation accumulating over 11 days, leading to an increased humidity level of 80% that can create a uniquely tropical feel. This combination of warmth and moisture sets September apart, offering a blend of moderate temperatures and occasional downpours, perfect for experiencing the vibrant autumn foliage while soaking in the lush landscape. For more detailed insights into Seongsu's weather patterns, visit Seongsu Climate.