Last updated: October 30, 2025
In Osan, South Korea, January brings a chilly embrace, with temperatures ranging from a maximum of 13°C (55°F) to a brisk minimum of -17°C (2°F), averaging around -2°C (29°F). The month sees a modest precipitation total of 21 mm (0.8 in) over just two days of rain, while humidity hovers at a comfortable 71%. This January weather paints a quintessential winter landscape, inviting both residents and visitors to experience the serene beauty of the season.
In Osan, South Korea, January brings a chill that can be felt deeply, with temperatures dipping to a frigid -17°C (2°F) at their lowest and peaking at a relatively mild 13°C (55°F). As the month progresses, the average temperature hovers around -2°C (29°F), marking it as one of the coldest periods of the year. The transition from winter to spring is evident as February follows, with slightly warmer temperatures ranging from -15°C (4°F) to 18°C (65°F), signaling the gradual shift towards milder weather. While January showcases the depths of winter's grasp, it sets the stage for the gentle rise in temperatures that follow, hinting at the rejuvenating changes that spring will soon bring.
In January, Osan, South Korea, experiences relatively low precipitation, with only 21 mm (0.8 in) of rain falling over just 2 days. This trend of minimal rainfall continues into February, slightly increasing to 23 mm (0.9 in), but still marked by few rainy days. As the seasons transition into spring, the precipitation levels rise significantly, doubling by March to 47 mm (1.9 in) and continuing to climb through April and May, where totals reach 54 mm (2.1 in) and 98 mm (3.9 in) respectively, accompanied by a noticeable increase in precipitation days. The summer months see a dramatic surge in rainfall, peaking in July and August with a whopping 235 mm (9.3 in) and 255 mm (10.1 in), highlighting Osan's propensity for heavy summer showers. Afterwards, the precipitation begins to taper off into the autumn, with September seeing 136 mm (5.4 in) before dropping again in October and November. Overall, January serves as a stark contrast to the subsequent months, marking the beginning of a steady rise in both precipitation amounts and rainy days leading into the wetter seasons.
In January, Osan, South Korea, experiences relatively high humidity at 71%, setting the stage for a trend that continues through the winter months. As the year progresses, humidity levels gradually decrease, reaching a lower 65% in both February and March. However, with the onset of spring and summer, moisture levels rise again, peaking at a notable 91% during the sweltering months of July and August. As the seasons shift towards autumn, humidity remains elevated at 77% in September before dropping to 74% in December. This cyclical pattern highlights Osan's humid climate, characterized by a significant spike in moisture during the summer months, while winter offers a brief respite.
In January, Osan, South Korea, experiences a moderate UV Index of 3, with a burn time of about 30 minutes under direct sunlight. As the month transitions into February, the UV Index rises slightly to 4, maintaining the moderate exposure category and the same burn time. However, by March, the UV Index jumps to 6, indicating a high level of risk and a reduced burn time of 25 minutes. This upward trend continues into the spring months, as very high UV levels peak in April and May, reaching 8 and 9, respectively, where outdoor enthusiasts should limit their sun exposure to just 15 minutes. The intensity escalates further in June, with an extreme UV Index of 10, prompting even shorter safe exposure times. As summer settles in, July and August maintain this extreme level at 11, enforcing a burn time as brief as 10 minutes. The trend begins to reverse in September, gradually declining to a UV Index of 9 and returning to very high status, but by October, it dips back to high at 6. November and December round out the year with a return to moderate UV levels of 4 and 3, respectively, both allowing for 30 minutes of sun exposure. For more detailed insights on UV levels throughout the year, visit Osan UV Index.
UV Risk Categories
In January, Osan, South Korea, welcomes the new year with 198 hours of sunshine, a gentle start to the brighter days ahead. As the months unfold, the sun begins to shine more vigorously; by February, it beams down for 242 hours, setting the stage for a steady increase. March brings 283 hours, and the sunlight continues to intensify into April with 289 hours. By the time May arrives, Osan basks in 315 hours, leading into the warm, sun-drenched days of June, which sees a peak of 318 hours—the month when the city is at its sunniest. As summer swelters through July and August, the hours only slightly diminish, averaging 293 and 290 hours respectively. Autumn ushers in a gradual decline, with September at 261 hours and October following with 266 hours. Surprisingly, November and December provide a respectable 231 and 235 hours, proving that even at the year's end, Osan holds onto its sunshine. The year thus weaves a warm tapestry of light, building up beautifully from the crisp beginnings of January to the vibrant heights of summer.
In January, Osan, South Korea, enjoys a sunny disposition with a 49% chance of sunshine. As winter deepens, the likelihood of clear skies starts to improve, leading into February, which boasts a slightly higher 53% chance. However, as spring approaches in March and April, the chances of sunny days dip to 43%, highlighting a seasonal fluctuation. Interestingly, while the middle of the year sees a decline in sunshine, August and September bring some relief with 31% and 39% chances, respectively. Overall, it’s evident that January marks a promising start to the year, as daylight gradually begins to wane and sunlight becomes a welcome sight amid the winter chill.
In Osan, South Korea, January begins with approximately 9 hours of daylight, a stark contrast to the vibrant 14 hours enjoyed in the heart of summer from June to July. This gradual increase in daylight is evident as February sees an additional hour, leading into March with 11 hours. As spring approaches, the days stretch longer, reaching 13 hours by April and maintaining that brightness through May. However, as summer wanes, daylight begins to recede, tapering off to 13 hours in August and winding down to 9 hours by December. This rhythmic cycle highlights the seasonal changes in Osan, with longer days paving the way for the warmer months, while winter brings a cozy return to shorter daylight, embodying the essence of each season.
In Osan, South Korea, the winds of January bring a brisk average speed of 3.1 m/s (7 mph), setting the tone for the winter months. As the seasons transition into February, the winds pick up slightly to 3.4 m/s (8 mph), reaching their peak for the year. However, by March, the wind calms down to 2.7 m/s (6 mph), and this downward trend continues through the summer, with July and August averaging around 2.0 m/s (4 mph) to 2.3 m/s (5 mph). Interestingly, as autumn arrives, wind speeds gradually increase again, stabilizing around 2.7 m/s (6 mph) and 2.4 m/s (5 mph) in October and November, before rising back to 2.9 m/s (7 mph) in December. This cycle highlights the seasonal rhythm of Osan’s winds, with January establishing a spirited start that ebbs into the gentler breezes of summer before reviving in the cooler months.
Weather in Osan varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Osan, focusing on differences in temperature, rainfall, humidity, and UV levels.
January typically brings colder temperatures compared to February, with lows dipping to -17°C (2°F) and an average of -2°C (29°F). In contrast, February sees slightly milder conditions, with an average temperature rising to 0°C (33°F) and a maximum of 18°C (65°F). While January experiences less precipitation at 21 mm (0.8 in) over just 2 days, February has a bit more precipitation at 23 mm (0.9 in) spread over 4 days. Humidity also varies slightly, being higher in January at 71% compared to February’s 65%. For more detailed weather information, you can check Osan weather in February.
January and March present distinct weather patterns, showcasing the transition from winter to early spring. In January, temperatures can plummet to a chilling minimum of -17°C (2°F), with an average of -2°C (29°F) and a maximum reaching 13°C (55°F). This month experiences limited precipitation, with only 21 mm (0.8 in) over just two days and a humidity level around 71%. Conversely, March brings a noticeable warming trend, where minimum temperatures rise to -6°C (21°F) and can peak at 21°C (70°F), resulting in an average of 7°C (44°F). Precipitation increases to 47 mm (1.9 in) over five days, and humidity decreases slightly to 65%. This climatic shift highlights the thawing landscape and the approach of spring. For more details on weather specifics in March, visit Osan weather in March.
In January, the weather is notably harsh, with temperatures ranging from a chilling minimum of -17°C (2°F) to a maximum of 13°C (55°F), averaging around -2°C (29°F). The month sees limited precipitation, with only 21 mm (0.8 in) over two days, and a humidity level of 71%. In contrast, April brings a significant shift, with temperatures rising to a minimum of -1°C (30°F) and reaching a comfortable maximum of 28°C (82°F), averaging 12°C (54°F). April experiences more precipitation, totaling 54 mm (2.1 in) spread over five days, and humidity increases slightly to 75%. For more details, you can check Osan weather in April.
January and May exhibit striking differences in weather conditions. In January, temperatures can plummet as low as -17°C (2°F), with an average of -2°C (29°F) and a maximum of 13°C (55°F). The month sees limited rainfall, with only 21 mm (0.8 in) recorded over just two days and a relative humidity of 71%. In contrast, May brings much warmer temperatures, with a minimum of 6°C (42°F), an average of 18°C (64°F), and highs reaching 31°C (89°F). This month is notably wetter, experiencing 98 mm (3.9 in) of precipitation across eight days, while humidity rises to 81%. For a detailed look at the weather patterns in May, visit Osan weather in May.
When comparing the weather in January and June, the contrasts are striking. In January, temperatures can plunge to a chilling low of -17°C (2°F), with an average hovering around -2°C (29°F) and a maximum reaching 13°C (55°F). The month sees light precipitation of 21 mm (0.8 in) occurring over just 2 days, accompanied by a humidity level of 71%. In stark contrast, June offers a warm welcome with minimum temperatures of 12°C (53°F) and averages around 22°C (72°F), peaking at a sweltering 33°C (91°F). This month experiences significantly higher rainfall, totaling 80 mm (3.1 in) over 7 days and a humidity level of 85%. For a closer look at the June climate, you can check out Osan weather in June.
January and July present starkly contrasting weather conditions. In January, temperatures can plummet to a minimum of -17°C (2°F) with an average of -2°C (29°F) and a maximum of 13°C (55°F). The month experiences minimal precipitation, averaging just 21 mm (0.8 in) over only 2 days, accompanied by a humidity level of 71%. In contrast, July boasts much warmer conditions with temperatures ranging from a minimum of 18°C (65°F) to a maximum of 36°C (98°F), averaging a balmy 26°C (79°F). Rainfall is significantly heavier, totaling 235 mm (9.3 in) over 14 days, and humidity rises to 91%. For a closer look at July weather specifics, visit Osan weather in July.
The weather in January and August presents a stark contrast in both temperature and precipitation. January sees frigid temperatures with a minimum of -17°C (2°F) and an average of -2°C (29°F), while August boasts much warmer conditions with temperatures ranging from a minimum of 16°C (61°F) to a maximum of 38°C (101°F). Precipitation levels also differ significantly, with January receiving only 21 mm (0.8 in) over just 2 days, compared to August, which experiences a substantial 255 mm (10.1 in) across 14 days. Additionally, humidity levels are higher in August at 91%, compared to 71% in January, further highlighting the seasonal differences. For more information, you can check Osan weather in August.
January and September present stark contrasts in weather. In January, temperatures plummet to a minimum of -17°C (2°F) with an average of -2°C (29°F), while maximums can reach 13°C (55°F). Precipitation is minimal, totaling just 21 mm over only 2 days, coupled with a humidity level of 71%. In contrast, September enjoys much milder conditions, with temperatures ranging from a minimum of 9°C (48°F) to a warm average of 22°C (71°F), and maximums soaring up to 31°C (88°F). The month is wetter, with precipitation of 136 mm over 9 days and slightly higher humidity at 77%. For more detailed insights, you can check out Osan weather in September.
In January, the weather is characterized by much colder temperatures, with a minimum of -17°C (2°F) and an average of -2°C (29°F), while October sees a much milder climate with temperatures ranging from a minimum of 1°C (33°F) to an average of 15°C (59°F). Precipitation also increases dramatically in October, with 62 mm (2.5 in) falling over five days compared to just 21 mm (0.8 in) over two days in January. Additionally, October experiences higher humidity levels at 79%, compared to January's 71%. For more details on the weather in October, you can check Osan weather in October.
The weather in January is significantly colder than in November, with temperatures ranging from a frigid -17°C (2°F) to a maximum of 13°C (55°F) and an average of -2°C (29°F). In contrast, November experiences milder conditions, with temperatures varying from a minimum of -5°C (23°F) to a pleasant maximum of 21°C (70°F) and an average of 8°C (46°F). Precipitation is also more prevalent in November, totaling 54 mm (2.1 in) over five days, compared to January’s mere 21 mm (0.8 in) over just two days. Additionally, humidity levels are higher in November at 80%, compared to January's 71%. For a closer look at November weather, check out Osan weather in November.
January weather is characterized by colder temperatures, with a minimum of -17°C (2°F) and an average of -2°C (29°F). In contrast, December has slightly milder conditions, featuring a minimum temperature of -14°C (8°F) and an average of 0°C (33°F). Both months experience similar maximum temperatures, with January peaking at 13°C (55°F) and December at 13°C (56°F). Precipitation is also less frequent in January, occurring on only 2 days and totaling 21 mm (0.8 in), while December sees more rainy days with 26 mm (1.0 in) of precipitation over 5 days. Humidity levels are slightly higher in December at 74%, compared to January's 71%. For a more detailed look at December weather, check out Osan weather in December.
January in Osan presents a notable departure from the milder seasons, with temperatures plunging to their annual lows and occasional bouts of chill. While the city often sees higher humidity levels even during winter, the low precipitation of just a couple of days keeps the landscape crisp and largely dry. This combination creates a bitter yet invigorating atmosphere, making January unique compared to the more temperate months that follow. For those looking to understand the subtleties of Osan’s climate, a deeper dive into the weather patterns can be found here: Osan Climate.