Last updated: October 30, 2025
December in Ulsan, South Korea, ushers in a cool and crisp atmosphere, with average temperatures hovering around 4°C (40°F). Residents can expect a comfortable maximum of 18°C (64°F) during the warmer days, but should be prepared for chilly nights when temperatures can dip to a brisk -9°C (17°F). With humidity levels at a notable 73%, the air can feel quite damp, particularly during the 3 days of precipitation, accumulating approximately 23 mm (0.9 in) of rainfall. This month beautifully embodies the transition into winter, inviting both locals and visitors to experience the serene charm of Ulsan.
In Ulsan, South Korea, December brings a noticeable chill as temperatures dip, with minimums reaching -9°C (17°F) and averages settling around 4°C (40°F). Against the backdrop of the previous months’ milder conditions, this transition underscores the onset of winter, yet daytime highs can still be surprisingly pleasant, peaking at 18°C (64°F). As the month progresses, the city shifts from the crisp air of late autumn to a steadier winter vibe, marking a significant cool-down from November’s milder temperatures. This blend of chill and occasional warmth makes December a unique time to experience Ulsan's winter landscape, inviting cozy activities and festive celebrations as the year draws to a close.
In December, Ulsan experiences a notable decrease in precipitation, with only 23 mm (0.9 in) recorded over just three rainy days. This dip follows the wettest months of the year, which peak in July and September, where rainfall often surpasses 200 mm. As temperatures cool, the transition into winter is marked by this reduced moisture, contrasting sharply with the summer deluge. The comparatively low precipitation in December signifies the end of a season characterized by heavy rain, making way for a drier winter period that lends a serene stillness to the city’s atmosphere.
In Ulsan, South Korea, December sees a humidity level of 73%, marking a slight decline from the preceding month's 75%. As the year draws to a close, the trend indicates a gradual decrease in humidity from the summer’s peak, where July and August experience remarkably high levels of 95% and 93%, respectively. This summer surge is followed by a decline in the fall, with humidity levels dipping to 80% in September and stabilizing in the cooler months of October and November. Overall, December’s humidity reflects the transition into winter, balancing on the cusp of moderate levels while still retaining some residual moisture from the preceding seasons. The fluctuating patterns throughout the year suggest a climate that embraces both the warmth of summer and the crispness of winter, making it a unique environment.
In Ulsan, South Korea, the UV Index in December presents a moderate level of exposure, registering at 3. This relatively low index indicates a burn time of 30 minutes, allowing for safe outdoor activities without heightened concern for skin damage. Observing the yearly trends, we see that the UV Index peaks in the summer months of June, July, and August, reaching an extreme level, while winter months like December and January keep UV exposure to a minimum. As the year wraps up, the moderate levels remind residents to stay mindful of sun safety, even in the cooler months. For detailed insights throughout the year, visit Ulsan UV Index.
UV Risk Categories
In Ulsan, South Korea, December ushers in a delightful blend of cooler temperatures and 244 hours of sunshine, marking a gentle decline from the peak of 307 hours in May. As the year comes to a close, the city experiences a gradual reduction in daylight, yet it still enjoys more sunshine than the winter months typically offer. Following a pattern of consistent brightness from spring through summer, December stands out with its moderate sunlight, echoing the vibrant energy of earlier months. This trend showcases Ulsan’s charm during the winter season, where the sun continues to grace the landscape even as it prepares for a new year.
In Ulsan, South Korea, the month of December stands out with a 77% chance of sunny weather, marking a significant increase compared to the preceding months. After a notable rise in November's sunny days at 70%, December not only maintains this positive trend but enhances it, making it one of the sunniest months of the year. This month contrasts sharply with the summer peak, where the likelihood of sunshine dwindles to 20% in July and only 24% in August. As the year draws to a close, December offers a refreshing burst of brightness, welcoming residents and visitors to enjoy outdoor activities under the clear skies before winter fully sets in.
As December arrives in Ulsan, South Korea, daylight takes a noticeable dip, offering just 9 hours of sunshine— the lowest of the year. This is a continuation of the gradual decline that began in late autumn, following a peak of 14 hours during the vibrant summer months of June to August. The shortening days reflect a pattern where springtime brings a gentle increase, starting from 10 hours in January and reaching 14 hours in May. The transition from the bright days of summer to the darkening winter serves as a reminder of the shifting seasons, culminating in this brisk December light that encourages cozy indoor moments as the year winds down.
In December, the winds in Ulsan, South Korea, pick up slightly, with an average speed of 3.7 m/s (8 mph), creating a refreshing chill that hints at the winter season ahead. This increase marks a subtle rise from the calmer summer months, where wind speeds hovered around 2.6 to 2.9 m/s, reflecting the area’s shift from warm, still air to brisk, invigorating breezes as the year closes. Interestingly, as autumn transitioned to winter, a trend emerged where wind speeds generally increased, contributing to the dynamic climate that Ulsan experiences. With December’s winds, the city embraces the beauty of the season—even as temperatures drop, the atmosphere is animated by the playful gusts that swirl through its coastal landscape.
Weather in Ulsan varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Ulsan, focusing on differences in temperature, rainfall, humidity, and UV levels.
December and January present a transition in winter weather, with January typically being cooler than December. In December, temperatures range from a minimum of -9°C (17°F) to a maximum of 18°C (64°F), with an average of 4°C (40°F). In contrast, January sees even lower minimum temperatures reaching -12°C (11°F) and a slightly lower average of 3°C (37°F), though the maximum is just a bit cooler at 16°C (62°F). Precipitation also increases in January to 32 mm (1.2 in), compared to December's 23 mm (0.9 in), although both months experience precipitation on three days. Humidity remains relatively stable, with December at 73% and January at 72%. For more detailed insights on January weather in Ulsan, check out Ulsan weather in January.
In December, temperatures range from a chilly minimum of -9°C (17°F) to a mild maximum of 18°C (64°F), with an average of 4°C (40°F). The month experiences relatively low precipitation at 23 mm (0.9 in) over about 3 days, accompanied by a humidity level of 73%. In contrast, February brings slightly warmer conditions, with temperatures still dipping to -9°C (15°F) but peaking at a more comfortable 23°C (73°F) and maintaining the same average of 4°C (40°F). Precipitation increases to 39 mm (1.5 in) across 4 days, and humidity declines slightly to 67%. For more details about the weather in February, you can visit Ulsan weather in February.
December and March showcase notable contrasts in weather patterns. In December, temperatures range from a chilly minimum of -9°C (17°F) to a maximum of 18°C (64°F), with an average of 4°C (40°F). The month features a relatively low precipitation level of 23 mm (0.9 in) across just 3 days, and humidity sits at a higher 73%. In contrast, March experiences milder temperatures, with a minimum of -2°C (29°F) and a maximum reaching 22°C (73°F), averaging 9°C (49°F). This month is significantly wetter, receiving 86 mm (3.4 in) of precipitation over 8 days, accompanied by a decrease in humidity to 65%. For more detailed information, check out Ulsan weather in March.
December and April present quite contrasting weather conditions. In December, temperatures can drop to a minimum of -9°C (17°F), with an average of 4°C (40°F) and a maximum of 18°C (64°F), accompanied by relatively low precipitation of 23 mm (0.9 inches) over just three days. The humidity level sits at 73%, contributing to a crisp winter feel. In contrast, April brings a milder climate with temperatures ranging from a minimum of 2°C (35°F) to a comfortable average of 14°C (57°F) and highs reaching up to 26°C (80°F). Precipitation in April is significantly higher, totaling 87 mm (3.4 inches) over seven days, while the humidity is slightly elevated at 75%. For more detailed insights, you can check Ulsan weather in April.
December and May present starkly contrasting weather profiles. In December, temperatures hover between a chilly minimum of -9°C (17°F) and a maximum of 18°C (64°F), with an average of 4°C (40°F). This month is characterized by limited precipitation, totaling 23 mm (0.9 in) over just three days, and a humidity level of 73%. Conversely, May boasts milder temperatures, ranging from a minimum of 6°C (43°F) to a sweltering maximum of 33°C (92°F), with an average temperature of 19°C (66°F). Precipitation in May is significantly higher at 80 mm (3.1 in), spread over eight days, and humidity also rises slightly to 83%. For more detailed insights into May weather, visit Ulsan weather in May.
December and June exhibit stark contrasts in weather conditions. In December, temperatures range from a chilly minimum of -9°C (17°F) to a mild maximum of 18°C (64°F), averaging around 4°C (40°F). The month experiences relatively low precipitation at 23 mm (0.9 in) over just 3 days, coupled with a humidity level of 73%. In contrast, June is significantly warmer, with temperatures ranging from a minimum of 13°C (56°F) to a maximum of 32°C (90°F), averaging 22°C (72°F). This month sees much higher precipitation at 144 mm (5.7 in) spread across 10 days, and humidity rises to 87%. For more detailed insights, visit Ulsan weather in June.
December and July present strikingly different weather patterns. In December, temperatures vary from a chilly -9°C (17°F) at their lowest to a mild average of 4°C (40°F), occasionally peaking at 18°C (64°F). The month experiences limited precipitation at 23 mm (0.9 in) over just 3 days, along with relatively high humidity around 73%. In contrast, July is characterized by much warmer temperatures, ranging from a minimum of 17°C (63°F) to an average of 26°C (78°F), with scorching highs of 36°C (98°F). It's also a much wetter month, with a total precipitation of 244 mm (9.6 in) spread over 14 days, and humidity levels soaring to 95%. For more detailed information, visit Ulsan weather in July.
December and August present starkly contrasting weather patterns. In December, temperatures can dip as low as -9°C (17°F), with an average of 4°C (40°F) and a maximum reaching 18°C (64°F). The month experiences low precipitation, totaling 23 mm (0.9 in) over just three days, and the humidity is relatively moderate at 73%. In sharp contrast, August boasts much warmer temperatures, with a minimum of 19°C (66°F) and an average of 27°C (81°F), peaking at a sweltering 36°C (98°F). This summer month is also significantly wetter, receiving 199 mm (7.8 in) of rain over 15 days and high humidity at 93%. For more details on August's climate, you can explore Ulsan weather in August.
In December, the weather is significantly colder, with temperatures ranging from a frigid minimum of -9°C (17°F) to a maximum of 18°C (64°F). Precipitation is relatively light, averaging just 23 mm (0.9 in) over about three days, and humidity sits at 73%. In contrast, September experiences much milder conditions, with temperatures ranging from a minimum of 13°C (56°F) to a warm maximum of 30°C (87°F). However, the month is quite wet, receiving 236 mm (9.3 in) of rainfall over approximately 12 days, and humidity levels are slightly higher at 80%. For more detailed insights on September weather patterns, you can refer to Ulsan weather in September.
December and October showcase significantly different weather patterns. In December, temperatures drop considerably, with a minimum of -9°C (17°F) and an average high of 4°C (40°F), contrasting sharply with October's milder climate, which boasts a minimum of 5°C (41°F) and an average high of 17°C (63°F). Additionally, October experiences far more precipitation at 100 mm (3.9 in) over 7 days, compared to December's relatively dry conditions with only 23 mm (0.9 in) over just 3 days. Humidity levels are also slightly higher in October at 77%, compared to December's 73%. For more detailed information, check out Ulsan weather in October.
In comparing December and November's weather, December experiences cooler temperatures, with a minimum of -9°C (17°F) and an average of 4°C (40°F), while November has milder conditions, with a minimum of -2°C (29°F) and an average of 11°C (52°F). The maximum temperatures also reflect this trend, peaking at 18°C (64°F) in December compared to 22°C (72°F) in November. Precipitation is slightly higher in December, with 23 mm (0.9 in) over three days, while November sees 21 mm (0.8 in) over the same number of days, and humidity levels remain fairly consistent at 73% in December and 75% in November. For more details, check out Ulsan weather in November.
As December rolls into Ulsan, the weather shifts notably, marking a transition from the milder autumn months to the chillier embrace of winter. With temperatures dipping to a brisk average of 4°C and occasional lows that reach -9°C, December contrasts sharply with the warmer periods that precede it. Although the month experiences minimal rainfall, measured at just 23 mm over three days, the increased humidity of 73% can make the cold feel more biting. This blend of cool temperatures and dampness invites residents and visitors alike to embrace warmer clothing and cozy indoor activities. To learn more about how Ulsan's climate varies throughout the year, visit Ulsan Climate.