September Weather in Daejeon, South Korea

Last updated: October 30, 2025

September in Daejeon, South Korea is characterized by a balmy average temperature of 21°C (70°F), peaking at a maximum of 30°C (87°F) while dropping to a refreshing minimum of 9°C (49°F) during the nights. The month witnesses 77% humidity, making the air feel quite warm and lush. Travelers should be prepared for some rain, as 176 mm (6.9 in) of precipitation falls over 9 days throughout the month, nurturing the vibrant greenery of this dynamic city. Overall, September is a month of comfortable warmth interspersed with refreshing showers, inviting exploration and outdoor activities.

September Temperature in Daejeon

In September, Daejeon experiences a delightful transition from the sizzling summer heat to a more temperate climate, making it a wonderful time to explore the city. With minimum temperatures hovering around 9°C (49°F) and averaging at 21°C (70°F), the days are pleasantly warm but not overly oppressive. The maximum temperatures reach up to 30°C (87°F), providing the perfect backdrop for outdoor activities or leisurely strolls through vibrant parks. This month's moderate weather signifies a shift from the intense heat of August, where temperatures soared into the high 30s, making September a refreshing pause before the cooler autumn months descend upon Daejeon.

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

The chart illustrates September temperature patterns in Daejeon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Daejeon, September typically has an average temperature of 21°C (70°F), with highs reaching up to 30°C (87°F) and lows dropping to around 9°C (49°F).
JanFebMarAprMayJunJulAugSepOctNovDec313446556573788070594634
Data source: Temperature data for Daejeon 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 Daejeon

In September, Daejeon experiences a significant dip in rainfall compared to the preceding summer months, yet it remains one of the wetter periods of the year. With 176 mm (6.9 in) of precipitation spread over 9 days, this month showcases a notable contrast to the deluge of July and August, where combined precipitation exceeded 400 mm. This transition into autumn brings more moderate rainfall alongside a decrease in wet days, highlighting a shift from the intense monsoon season. As the landscape transforms, September's rains nourish the vibrant hues of fall, ensuring a beautiful backdrop for the city's seasonal change.

September Precipitation Trends in Daejeon

The chart displays monthly precipitation patterns in Daejeon, 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 Daejeon, September typically receives around 176 mm (6.9 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec233664668297214221177683626
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Daejeon

September in Daejeon, South Korea, marks a notable shift in humidity, dropping to 77% after the peak of the summer months. Following the sweltering July and August, where humidity levels soared to an uncomfortable 91%, September offers a welcome reprieve. This decrease signals the transition from the oppressive summer heat towards the more temperate autumn season. While humidity remains elevated compared to the winter months, the slight decline hints at a refreshing change, as the city experiences milder temperatures and a gradual onset of crisp fall air. Overall, September serves as a bridge, blending the lingering warmth of summer with the refreshing coolness of autumn.

September Average Humidity in Daejeon

This chart illustrates the average monthly humidity levels in Daejeon, 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 Daejeon is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec71%65%65%75%81%85%91%91%77%79%80%74%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Daejeon

As summer fades into autumn in Daejeon, South Korea, September showcases a UV Index of 10, categorizing it as very high with a burn time of just 15 minutes. Following the extreme conditions of July and August, this slight drop still calls for caution when enjoying outdoor activities. The trend throughout the year reveals a gradual increase during the warmer months, peaking at 12 in August, before tapering off as the cooler fall months approach. As the UV Index starts to decline in October, now is the perfect time to balance sun exposure with protection. For more detailed insights, visit the Daejeon UV Index.

Maximum UV Index Levels in Daejeon for September

The chart shows the monthly maximum UV Index (UVI) for Daejeon 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 Daejeon typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579911111210753
Data source: Daejeon 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 Daejeon

September in Daejeon, South Korea, offers a delightful respite as summer transitions into autumn, with 243 hours of sunshine lighting up the days. This month reflects a slight dip from the sun-soaked peaks of late spring and early summer, where May basked in a remarkable 303 hours and June followed closely with 301 hours. As the year progresses, the sunshine hours tend to wane, with July and August still holding on to a fair amount of radiant days at 265 and 273 hours respectively. However, September's balance of bright days and cooling breezes sets the stage for a cozy autumn, making it an ideal time for outdoor activities. This shift continues into October, where the daylight hours gradually decrease, paving the way for the tranquil beauty of fall.

Monthly Sunshine Duration in Daejeon: September Highlighted

The September sunshine duration represents the total number of hours Daejeon 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.
JanFebMarAprMayJunJulAugSepOctNovDec194h236h276h279h303h301h265h273h243h258h229h236h
Data source: Daejeon September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Daejeon During September

September in Daejeon, South Korea, presents a moderate likelihood of sunny weather, boasting a 37% chance of sunshine. This continues a trend of declining sun exposure from the vibrant summer months, where July and August experienced their lowest figures at 26% and 28% respectively. As the year transitions into autumn, September falls just above May and June, which both sit at 36%, suggesting a potential for clearer days without fully shaking off the remnants of the wet season. Looking ahead, the likelihood of sunny days significantly increases in October to 51%, marking a delightful shift as the season advances. Overall, September serves as a transitional month, hinting at both the lingering warmth and the approaching clarity of fall.

Percentage of Sunny Days in September in Daejeon

The chart illustrates the percentage of sunny days in Daejeon 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 Daejeon experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec45%49%40%42%37%36%26%28%37%51%59%60%
Data source: Daejeon September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Daejeon in September

As summer transitions into autumn, September in Daejeon, South Korea, showcases a gentle decline in daylight, offering about 12 hours of light each day. This marks a subtle shift from the peak daylight of 14 hours experienced in the summer months of June, July, and August. The daylight gradually tapers off as it moves into October, where it dips to 11 hours. This natural ebb and flow highlights the region's rhythmic shift in seasons, creating a balance between the vibrant energy of summer and the cozy embrace of fall. With the days gradually getting shorter, September invites residents to savor the lingering warmth while preparing for the cooler months ahead.

Average Daylight Hours in Daejeon for September

The chart illustrates the variation in daylight duration in Daejeon throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 58m10h 50m11h 57m13h 7m14h 5m14h 34m14h 19m13h 28m12h 22m11h 14m10h 14m9h 43m
Data source: Daejeon daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Daejeon

As September rolls into Daejeon, South Korea, the wind begins to pick up slightly, with an average speed of 2.9 m/s (6 mph). This marks a gentle resurgence compared to the calmer summer months, where the wind languished at a steady 2.1 m/s. Interestingly, September’s breezy conditions are reminiscent of the spring months, particularly April, which also reported an average wind speed of 3.0 m/s. While the summer heat typically offers little respite from the stillness, September transitions into a more invigorating atmosphere, hinting at the upcoming fall while maintaining a consistent tempo seen in the late autumn months of November and December.

Average September Wind Speed in Daejeon

The chart displays monthly wind speed patterns in Daejeon, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.83.32.53.02.92.12.12.12.9 m/s2.12.52.7
Data source: Daejeon September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Daejeon Compares to Other Months

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

September and January showcase stark contrasts in weather. September experiences a warm temperature range, with lows of 9°C (49°F) and highs reaching up to 30°C (87°F), accompanied by significant rainfall of 176 mm (6.9 in) over about 9 days, resulting in a humid atmosphere with 77% humidity. In contrast, January presents a chilling scenario, where temperatures plunge to a minimum of -19°C (-2°F), peaking at just 13°C (57°F). Precipitation is minimal during this month, totaling only 23 mm (0.9 in) across 4 days, and humidity levels drop to 71%. For a closer look at January conditions, you can visit Daejeon weather in January.

September and February present striking contrasts in weather patterns. In September, temperatures range from a minimum of 9°C (49°F) to a maximum of 30°C (87°F), with an average of 21°C (70°F). The month also sees significant rainfall, accumulating 176 mm (6.9 in) over about 9 days, accompanied by high humidity at 77%. In contrast, February experiences a much colder climate, with temperatures dipping to a minimum of -15°C (6°F), reaching an average of 1°C (34°F), and peaking at 21°C (71°F). Precipitation is scarce in February, totaling just 35 mm (1.4 in) over approximately 4 days, and humidity levels are lower at 65%. For more detailed insights, you can check the full report on Daejeon weather in February.

September and March present contrasting weather patterns. September boasts warmer temperatures with a minimum of 9°C (49°F) and an average of 21°C (70°F), reaching highs of 30°C (87°F). In contrast, March experiences cooler weather, starting with a minimum of -5°C (24°F) and only averaging 8°C (46°F), peaking at 24°C (75°F). Precipitation is notably higher in September, with 176 mm (6.9 in) over 9 days compared to March's more modest 63 mm (2.5 in) across 7 days. The humidity levels also differ, with September at 77% and March at 65%. For more detailed weather information, you can check Daejeon weather in March.

When comparing the weather in September and April, September typically offers warmer temperatures, with average highs reaching up to 30°C (87°F), while April has a more moderate average temperature of 13°C (56°F). Despite the warmer temperatures, September also experiences higher precipitation, averaging 176 mm (6.9 in) over about 9 days, compared to April's 66 mm (2.6 in) over 6 days. Humidity levels are relatively similar, with September at 77% and April at 75%. For those interested in more specific details about the weather in April, you can visit Daejeon weather in April.

In comparing the weather of September and May, we see distinct differences in temperature and precipitation. September experiences a broader temperature range with a minimum of 9°C (49°F) and an average of 21°C (70°F), peaking at a warm 30°C (87°F). In contrast, May has cooler overall temperatures, with a minimum of 4°C (39°F), an average of 18°C (65°F), and a maximum reaching 31°C (89°F). Rainfall is notably higher in September, accumulating 176 mm (6.9 in) over 9 days, compared to May's 82 mm (3.2 in) over the same number of days. Humidity levels are also slightly different, with September at 77% and May at 81%. For more detailed information, you can check Daejeon weather in May.

When comparing the weather in September and June, one can observe notable differences in temperature and precipitation. September typically has a minimum temperature of 9°C (49°F) and averages around 21°C (70°F), reaching a maximum of 30°C (87°F). In contrast, June starts with a slightly higher minimum of 11°C (52°F) and an average of 23°C (73°F), with peak temperatures hitting 35°C (95°F). Precipitation in September is more pronounced, with totals reaching 176 mm (6.9 in) over 9 days, compared to June's 97 mm (3.8 in) over 8 days. Additionally, humidity levels are higher in June at 85%, compared to September’s 77%. For a more detailed look at June weather, check out Daejeon weather in June.

September and July exhibit notably different weather patterns. In September, temperatures range from a cooler minimum of 9°C (49°F) to a comfortable maximum of 30°C (87°F), with an average of 21°C (70°F). The month sees 176 mm (6.9 in) of rainfall over 9 days, and the humidity averages 77%. In contrast, July is significantly warmer, with temperatures ranging from a minimum of 17°C (62°F) to a scorching maximum of 38°C (100°F) and an average of 26°C (78°F). July also experiences higher precipitation, totaling 214 mm (8.4 in) over 16 days, along with increased humidity at 91%. For more detailed information about July weather in Daejeon, you can visit Daejeon weather in July.

In comparing the weather of September and August, we see notable differences in temperature and precipitation patterns. September experiences a more moderate temperature range, with minimums around 9°C (49°F) and maximums reaching 30°C (87°F), leading to an average of 21°C (70°F). In contrast, August is significantly warmer, with minimums of 16°C (61°F) and maximums soaring to 39°C (102°F), resulting in a higher average of 27°C (80°F).

Precipitation in September totals 176 mm (6.9 in) over 9 days, while August is wetter, featuring 221 mm (8.7 in) spread over 16 days. Humidity levels are also higher in August at 91%, compared to 77% in September. For a more detailed look at the weather data for August, you can visit Daejeon weather in August.

In September, the weather is characterized by a warm average temperature of 21°C (70°F), with daytime highs reaching up to 30°C (87°F) and relatively high humidity at 77%. Rainfall is also significant during this month, totaling 176 mm (6.9 in) over approximately 9 days. In contrast, October brings cooler temperatures, with an average of 15°C (59°F) and nighttime lows dropping to 0°C (33°F). Despite the noticeable drop in temperature, October experiences a maximum high of 31°C (88°F), making it potentially warm at times. Additionally, precipitation decreases to 68 mm (2.7 in) over just 5 days, while humidity remains slightly higher at 79%. For a detailed overview of what to expect, see Daejeon weather in October.

In September, the weather is typically warm with temperatures ranging from a minimum of 9°C (49°F) to a maximum of 30°C (87°F), averaging around 21°C (70°F). This month experiences more precipitation, totaling 176 mm (6.9 in) over about 9 days, with humidity levels at 77%. In contrast, November brings a significant drop in temperature, with a minimum of -4°C (24°F) and an average of 8°C (47°F), while the maximum remains the same as September at 21°C (70°F). Rainfall is less frequent in November, with only 36 mm (1.4 in) over 5 days, and slight increases in humidity at 80%. For more information, you can check Daejeon weather in November.

September and December present stark contrasts in weather. In September, temperatures range from a minimum of 9°C (49°F) to a maximum of 30°C (87°F), with an average of 21°C (70°F), creating a warm and humid atmosphere with 176 mm of precipitation over 9 days and a humidity level of 77%. In contrast, December brings a chill, with temperatures dipping significantly, ranging from -14°C (6°F) at night to a maximum of 16°C (61°F) during the day, and an average of just 1°C (34°F). Precipitation in December is much lower, at 26 mm across 4 days, and the humidity slightly decreases to 74%. For more details about the winter weather, you can visit Daejeon weather in December.

Compare Daejeon's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Daejeon

As September unfolds in Daejeon, the weather presents a delightful transition from the summer's heat to the cooler embrace of autumn. With an average temperature of around 21°C (70°F), the month contrasts significantly with the soaring highs of summer, inviting residents and visitors alike to enjoy more temperate days and crisp evenings. Humidity remains high, often hovering around 77%, adding a lingering tropical feel, but it is balanced by a noticeable drop in temperatures compared to July and August. Rainfall is also on the rise, with about 176 mm of precipitation spread over 9 days, further softening the summer remnants. Overall, September in Daejeon is a month of refreshing change, offering a perfect backdrop for outdoor activities and a chance to witness the early signs of autumn's beauty. For more in-depth information about the weather throughout the year, visit Daejeon Climate.