September Weather in Wonju, South Korea

Last updated: October 30, 2025

September in Wonju, South Korea brings a pleasant blend of warm days and cool nights, with maximum temperatures reaching up to 29°C (85°F) and an average of 20°C (68°F). The month is characterized by significant humidity levels at 77%, contributing to a vibrant, lush environment. However, residents and visitors should be prepared for occasional rain, as 154 mm (6.1 in) of precipitation falls over 10 days. Despite the moisture, September remains an ideal time to experience the beauty of Wonju's early autumn foliage and enjoy the delightful outdoor activities the season has to offer.

September Temperature in Wonju

In September, Wonju, South Korea, experiences a delightful transition from the sweltering summer to the refreshing embrace of autumn. With minimum temperatures hovering around 6°C (44°F) and comfortable averages reaching 20°C (68°F) during the day, the weather is pleasantly mild. The maximum temperature peaks at 29°C (85°F), allowing for warm afternoons ideal for outdoor activities. This month marks a significant cooldown from the heat of August, showcasing a gradual decline in temperatures as the region prepares for the cooler months ahead. The shift not only enhances the landscape with vibrant fall foliage but also invites residents and visitors alike to savor the gradual change in seasons.

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

The chart illustrates September temperature patterns in Wonju, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Wonju, September typically has an average temperature of 20°C (68°F), with highs reaching up to 29°C (85°F) and lows dropping to around 6°C (44°F).
JanFebMarAprMayJunJulAugSepOctNovDec273143536371767768564330
Data source: Temperature data for Wonju generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Wonju

September in Wonju, South Korea, marks a significant transition in precipitation patterns, as the city receives 154 mm (6.1 in) of rainfall over 10 days. This sharp decline from the intense monsoon months of July and August, which saw 242 mm (9.5 in) and 258 mm (10.2 in) respectively, signals the gradual shift towards drier autumn conditions. While September's rainfall is substantial, it is markedly less than the summer peak, indicating a seasonal tapering that prepares the region for the incoming crispness of fall. Overall, this month serves as a bridge between the heavier rains of summer and the lighter, more sporadic showers expected in October and November.

September Precipitation Trends in Wonju

The chart displays monthly precipitation patterns in Wonju, 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 Wonju, September typically receives around 154 mm (6.1 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec2432648411092243258154675225
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Wonju

In September, Wonju, South Korea, experiences a notable dip in humidity at 77%, providing a slight reprieve from the oppressive levels seen during the peak summer months of July and August, which both reached a steamy 91%. This transitional month hints at the impending fall, as humidity levels begin to balance out following the summer highs, though they still remain above the annual average. As the year progresses, September sets the stage for the fluctuating humidity of autumn, which hovers around 78% in October and 80% in November. This gradual decline illustrates a natural ebb and flow in humidity that characterizes Wonju's climate, offering a refreshing contrast to the sultry summer.

September Average Humidity in Wonju

This chart illustrates the average monthly humidity levels in Wonju, 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 Wonju is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec71%66%64%74%79%82%91%91%77%78%80%76%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Wonju

As summer transitions to fall in September, Wonju experiences a UV Index of 10, categorizing it as very high exposure. This marks a slight decrease from the intense readings of August, which peaked at 12. With a shorter burn time of just 15 minutes, it's vital to remain vigilant about sun protection during outdoor activities this month. Interestingly, this trajectory shapes a trend of gradually diminishing UV levels as the year progresses, moving from extreme in the summer months to more moderate levels by November. For more details on how to stay protected, visit Wonju UV Index.

Maximum UV Index Levels in Wonju for September

The chart shows the monthly maximum UV Index (UVI) for Wonju 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 Wonju typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3469911111210743
Data source: Wonju 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 Wonju

In September, Wonju basks in the tail end of summer, enjoying 251 hours of sunshine. This marks a delightful transition from the peak of summer in June, which boasts the highest sunshine hours at 310 hours. As the seasons change, September holds its own, outshining the earlier months of the year, like January with only 199 hours. While there’s a noticeable dip compared to the sun-drenched days of June and May, September’s cloud-kissed skies still promise plenty of bright moments, welcoming autumn with a gentle embrace. As the days grow shorter, the sunshine serves as a warm reminder of the vibrant summer that was, while hinting at the cooler months ahead.

Monthly Sunshine Duration in Wonju: September Highlighted

The September sunshine duration represents the total number of hours Wonju 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.
JanFebMarAprMayJunJulAugSepOctNovDec199h239h274h281h304h310h279h264h251h258h233h239h
Data source: Wonju September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Wonju During September

In September, Wonju, South Korea, experiences a 35% chance of sunny weather, which is relatively stable compared to the summer months but marks a slight uptick from the peak of July and August, where the sun shines just 29% and 25% of the time, respectively. This transition into autumn typically brings more favorable conditions, with sunny days becoming more likely as the season advances, paving the way for a 45% chance in October and a return to 55% in November. Thus, while September's sun probability may not be as high as the winter months, it stands as a refreshing bridge from the sultry summer, setting the stage for the clearer skies that follow.

Percentage of Sunny Days in September in Wonju

The chart illustrates the percentage of sunny days in Wonju 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 Wonju experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec57%55%42%42%35%36%29%25%35%45%55%64%
Data source: Wonju September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Wonju in September

In September, daylight in Wonju, South Korea, begins to transition from the warm, sun-drenched days of summer to the cooler embrace of autumn. With approximately 12 hours of daylight, September marks a subtle decline from the summer peak of 14 hours in June through August. As the month progresses, the days shorten, reflecting a natural rhythm that prepares the region for the changing seasons. This gradual reduction in daylight captures the essence of early fall, where longer evenings invite cozy gatherings and a chance to savor the vibrant hues of nature as it shifts.

Average Daylight Hours in Wonju for September

The chart illustrates the variation in daylight duration in Wonju throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 53m10h 47m11h 57m13h 9m14h 10m14h 40m14h 25m13h 32m12h 23m11h 12m10h 9m9h 37m
Data source: Wonju daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Wonju

As September unfolds in Wonju, South Korea, the gentle breeze begins to stir, with an average wind speed of 2.0 m/s (4 mph). This slight uptick from the summer months, where wind speeds lingered around 1.6 to 1.8 m/s, signals a subtle shift in the atmosphere as autumn approaches. Following the more tranquil summer, September's winds act as a precursor to the seasonal change, offering a refreshing reprieve and hinting at the crisp air of fall. As temperatures start to cool, this moderate wind serves as a harbinger of the more dynamic weather patterns expected in the months ahead, with October and November bringing back stronger gusts typical of the transition into winter. Thus, September’s weather sets the stage for nature’s beautiful evolution in Wonju.

Average September Wind Speed in Wonju

The chart displays monthly wind speed patterns in Wonju, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.52.82.32.42.31.81.61.72.0 m/s1.82.22.4
Data source: Wonju September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Wonju Compares to Other Months

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

September and January present strikingly different weather patterns. In September, temperatures typically range from a mild 6°C (44°F) at night to a warm average of 20°C (68°F) during the day, peaking at a high of 29°C (85°F). This month also sees considerable rainfall with approximately 154 mm (6.1 in) over about 10 days, contributing to a relatively high humidity level of 77%. In contrast, January is characterized by much colder temperatures, with nighttime lows plunging to -20°C (-3°F) and average daytime highs around -3°C (28°F), reaching a maximum of only 12°C (54°F). Precipitation is notably less in January, totaling just 24 mm (0.9 in) over about 4 days, accompanied by lower humidity at 71%. For a detailed look at the January weather in this region, you can refer to Wonju weather in January.

September and February present stark contrasts in weather conditions. In September, temperatures range from a mild 6°C (44°F) at night to a warm 29°C (85°F) during the day, accompanied by an average temperature of 20°C (68°F). The month experiences significant humidity at 77% and a total precipitation of 154 mm (6.1 in) over approximately 10 days. In contrast, February offers a much colder climate, with temperatures plunging to a chilling minimum of -17°C (2°F) and a daily maximum of 19°C (66°F), averaging around 0°C (32°F). Precipitation is minimal at 32 mm (1.2 in) over just 4 days, and humidity is lower at 66%. For more details on February weather, you can visit Wonju weather in February.

September and March exhibit stark contrasts in weather patterns. September boasts warmer temperatures with an average of 20°C (68°F) and highs reaching 29°C (85°F), while March is cooler, with an average of only 6°C (44°F) and highs topping at 21°C (70°F). Precipitation is more significant in September, with 154 mm (6.1 in) over 10 days, compared to March’s lighter rainfall of 64 mm (2.5 in) over 7 days. Additionally, humidity levels are higher in September at 77%, while March experiences a lower humidity of 64%. For a detailed look at the weather in March, visit Wonju weather in March.

When comparing the weather in September and April, notable differences emerge. September boasts a much warmer average temperature of 20°C (68°F), with maximum highs reaching up to 29°C (85°F), while in April, the average temperature is cooler at 12°C (53°F), with maximums only reaching 27°C (81°F). Precipitation is more prevalent in September, with 154 mm (6.1 in) expected over about 10 days, compared to April's 83 mm (3.3 in) across 7 days. Additionally, September has a higher humidity level at 77%, compared to April's 74%. For more details about April weather, you can visit Wonju weather in April.

In comparing the weather between September and May, notable differences emerge in both temperature and precipitation. September typically enjoys warmer temperatures, ranging with an average of 20°C (68°F) and reaching a maximum of 29°C (85°F), while May's average temperature is slightly cooler at 17°C (63°F), though it can peak at 31°C (88°F). Precipitation levels in September are higher, totaling 154 mm (6.1 in) over about 10 days, compared to May’s 110 mm (4.3 in) for the same duration. Humidity levels are relatively similar in both months, with September at 77% and May slightly higher at 79%. For more detailed insights, you can explore Wonju weather in May.

When comparing the weather in September and June, notable differences emerge in temperature and rainfall patterns. September experiences a wider temperature range with a minimum of 6°C (44°F) and a maximum of 29°C (85°F), while June is warmer overall with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 33°C (91°F). Despite both months receiving similar amounts of rainfall, September's precipitation is significantly higher at 154 mm (6.1 in) over 10 days compared to June's 92 mm (3.6 in) over 9 days. Additionally, humidity levels in June are slightly higher at 82%, compared to 77% in September. For more detailed information about June weather in Wonju, you can visit Wonju weather in June.

When comparing the weather in September and July, there are notable differences in temperature and precipitation. September enjoys a milder temperature range, with minimums around 6°C (44°F) and average highs of 29°C (85°F), while July is significantly warmer, with minimums of 15°C (59°F) and maximums reaching 35°C (95°F). Rainfall is also heavier in July, with 242 mm (9.5 in) of precipitation over 16 days, compared to September's 154 mm (6.1 in) spread over 10 days. Additionally, the humidity is higher in July at 91%, compared to September's 77%. For a closer look at July's weather, visit Wonju weather in July.

When comparing the weather of September and August, it's clear that September experiences cooler temperatures, with minimums dropping to 6°C (44°F) and average highs of 29°C (85°F), compared to August's milder minimum of 13°C (56°F) and maximums soaring up to 37°C (99°F). Precipitation is also higher in August, totaling 258 mm (10.2 in) over 17 days, while September sees a marked reduction with 154 mm (6.1 in) over just 10 days. Additionally, humidity levels in August are notably higher at 91%, compared to 77% in September. For more detailed insights on August weather, please visit Wonju weather in August.

September and October showcase a notable transition in weather patterns. In September, temperatures range from a minimum of 6°C (44°F) to a maximum of 29°C (85°F), with an average of 20°C (68°F). This month typically experiences higher precipitation, totaling 154 mm (6.1 in) over about 10 days, and a humidity level of 77%. In contrast, October sees a drop in both average temperatures and overall rainfall. The minimum temperature can fall to -1°C (30°F), while the maximum hovers around 28°C (83°F), resulting in an average of 13°C (56°F). Precipitation decreases significantly to 67 mm (2.6 in) over only 6 days, with humidity slightly rising to 78%. For more details, you can check out Wonju weather in October.

September and November present a striking contrast in weather, reflecting the transition from late summer to early winter. In September, temperatures range from a mild 6°C (44°F) at night to a warm 29°C (85°F) during the day, with an average of 20°C (68°F). The month experiences relatively high humidity at 77% and receives significant rainfall with 154 mm (6.1 in) over 10 days. In stark contrast, November brings cooler temperatures, with nighttime lows plunging to -7°C (20°F) and daytime highs maxing out at 20°C (68°F), averaging only 6°C (43°F). This month sees less rain, with only 52 mm (2.1 in) over 6 rainy days, and slightly higher humidity levels at 80%. For an in-depth look at November weather in Wonju, check out Wonju weather in November.

September and December present contrasting weather experiences. In September, temperatures range from a mild 6°C (44°F) at night to a warm 29°C (85°F) during the day, with an average of 20°C (68°F). This month sees considerable rainfall, averaging 154 mm (6.1 in) over about 10 days, and the humidity sits at a relatively high 77%. In stark contrast, December brings much colder conditions, with temperatures plummeting to a minimum of -24°C (-11°F) and a maximum of 12°C (53°F), averaging around -1°C (30°F). Precipitation is significantly lower in December, with only 25 mm (1.0 in) over 5 days, and humidity levels remain similar at 76%. For more details on December weather specifics, visit Wonju weather in December.

Compare Wonju's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Wonju

As summer gradually gives way to autumn, September in Wonju offers a delightful transition characterized by mild temperatures and increased humidity. With daytime highs reaching a comfortable 29°C and cooler nights dropping to a refreshing 6°C, the month provides a perfect balance for outdoor activities. However, it also brings a notable increase in rainfall, with approximately 154 mm falling over 10 days, making it one of the wetter months of the year. This shift in weather sets September apart, as vibrant autumn colors begin to emerge, offering a scenic backdrop for both residents and visitors. To explore more about Wonju's unique weather patterns, check out Wonju Climate.