Last updated: August 28, 2025
In Ulan Bator, Mongolia, December brings a distinctly frigid climate, with an average temperature plummeting to -21°C (-5°F), and extreme lows dipping as low as -39°C (-38°F). Despite the chill, the month remains almost completely dry, recording only 3 mm (0.1 in) of precipitation across zero days of rain. Humidity hangs at a high 89%, adding to the biting cold and creating a crisp atmosphere typical of this northern city during winter. Visitors should prepare for the severe temperatures while enjoying the unique beauty of a snow-covered landscape.
In December, Ulan Bator experiences some of its coldest temperatures of the year, with minimums plunging to -39°C (-38°F) and an average hovering around -21°C (-5°F). The days remain chilly, as maximum temperatures barely rise to -3°C (28°F), making it a time where warm clothing is essential for braving the frigid air. This month continues the trend of extreme cold, building on the substantial drops seen in November, where temperatures dipped to as low as -35°C (-32°F). As winter fully settles in, December encapsulates the harsh beauty of Mongolia’s cold season, creating a stark contrast to the mild temperatures that emerge later in spring.
December in Ulan Bator marks a significant lull in precipitation, with only 3 mm (0.1 in) recorded, reflecting the dry patterns characteristic of winter. Notably, this month experiences no precipitation days, continuing a trend of minimal rainfall that began in late autumn. As the city transitions into the colder months, the overall decline in moisture is evident; from the peak rainfall in summer months, which see up to 83 mm in August, the contrast becomes stark as January to December averages drop dramatically. This seasonal shift highlights Ulan Bator's extreme continental climate, where the long, frigid winters dominate, leaving scant moisture in their wake.
December in Ulan Bator, Mongolia, witnesses a notable spike in humidity, reaching 89% as the year draws to a close. This increase stands out distinctly against the lower humidity levels experienced in earlier months, with November clocking in at 67% and October stabilizing around 65%. The trend showcases a gradual ascent from the driest months of late spring, where May enjoys a refreshing 50% humidity, toward the winter season's characteristic moisture. This rise in December’s humidity can be attributed to the cooler temperatures and the onset of winter, making the air feel more humid despite the frigid conditions. As 2023 bids farewell, Ulan Bator wraps up the year with a reminder of its climatic extremes, where sharp contrasts between seasons are vividly felt.
Throughout the year in Ulan Bator, Mongolia, the UV Index experiences significant fluctuations, peaking at very high levels during the summer months of May to August, when it reaches 9, indicating a strong need for sun protection with a burn time as short as 15 minutes. As the seasons transition towards winter, the UV Index begins to decline, revealing a much gentler 1 in December. This low exposure category translates to a safer environment for outdoor activities, with a burn time of 45 minutes. Surprisingly, despite the cold, December sunlight remains a reminder of the sun's presence, continuing the tradition of monitoring UV levels year-round. For a detailed overview of UV exposure in this unique location, check out the Ulan Bator UV Index.
UV Risk Categories
December in Ulan Bator brings a modest 250 hours of sunshine, a softer glow in a year otherwise bursting with warmth and light. As the year transitions from the vibrant spring and summer months—where sunshine peaked at 376 hours in May—there's a noticeable decline toward winter. The sun's brilliance sees a gradual descent, dropping from the previous month's 263 hours. Despite this decrease, December's daylight still holds a charm against the stark, cold landscape, inviting residents and travelers alike to appreciate the unique beauty of a sunlit winter day. The shift serves as a reminder of the city's deep seasonal contrasts, where each month tells its own story through the changing light.
As December settles in Ulan Bator, the likelihood of sunny weather reaches an encouraging 75%, making it one of the sunniest months of the year. This marks a notable increase from the preceding months, particularly the gradual rise observed since October's 69% and November's 65% chances of sunshine. The trend suggests a delightful shift as winter approaches, providing residents and visitors alike with ample opportunities to embrace the crisp air under brighter skies. Given the historical context, December not only stands out for its sunny disposition but also highlights a compelling transition from the more subdued sunlight seen during the earlier months.
As the year winds down, December in Ulan Bator, Mongolia, brings a return to shorter days, with only 8 hours of daylight. This marks a continuation of the decline that begins in late autumn, after a gradual increase in sunlight from the depths of winter in January. The transition is noticeable as daylight hours start their ascent in February, peaking at 15 hours during the vibrant summer months of June through August. Following this peak, the daylight duration slowly tapers off, leading into the colder, darker days of late fall and early winter. Thus, December not only signifies the onset of winter but also highlights the cyclical nature of daylight in this northern city, where each season brings its unique rhythm to the everyday life of its residents.
As December settles in Ulan Bator, the average wind speed drops to a gentle 2.4 m/s (5 mph), reflecting a notable trend of decreasing gusts as winter approaches. Throughout the months, wind speeds fluctuate slightly, peaking in April at 3.4 m/s (8 mph) before beginning a gradual decline that continues into the colder months. This consistent drop suggests a transition to stiller conditions typical of Mongolia's harsh winters, where the biting cold increasingly dominates the atmosphere and the need for warm layers becomes paramount. The calmness of December's winds adds to the serene, yet stark beauty of this vibrant city, inviting locals and visitors alike to embrace the crisp air and stunning winter landscapes.
Weather in Ulan Bator varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Ulan Bator, focusing on differences in temperature, rainfall, humidity, and UV levels.
In December, the weather in Ulan Bator features a minimum temperature of -39°C (-38°F) and an average of -21°C (-5°F), with a maximum reaching -3°C (28°F). Precipitation during the month is minimal, totaling just 3 mm (0.1 in) over zero days, and the humidity sits at a high 89%. In contrast, January is even colder, with temperatures dipping to a minimum of -42°C (-44°F) and an average of -22°C (-8°F), while the maximum is slightly higher at -5°C (23°F). Precipitation is slightly lower at 2 mm (0.1 in) with no rainy days, but the humidity increases to 92%. For more detailed information on January's weather, you can visit Ulan Bator weather in January.
December weather in Ulan Bator is characterized by extremely cold temperatures, with an average of -21°C (-5°F) and a maximum of only -3°C (28°F). The month sees minimal precipitation, with just 3 mm (0.1 in) reported over zero days, resulting in high humidity levels at 89%. In contrast, February experiences a slight warming trend, with an average temperature of -18°C (0°F) and a maximum reaching 4°C (39°F). While precipitation increases to 5 mm (0.2 in) over one day, the humidity decreases to 84%. For more detailed information on February weather in Ulan Bator, visit Ulan Bator weather in February.
In December, the weather is characterized by severe cold, with temperatures ranging from a minimum of -39°C (-38°F) to an average of -21°C (-5°F), reaching a maximum of just -3°C (28°F). The month sees very little precipitation, recording only 3 mm (0.1 in) over zero days, and remains quite humid at 89%.
In contrast, March experiences a notable shift, with temperatures ranging from a minimum of -29°C (-20°F) to an average of -7°C (20°F) and peaking at a much milder 16°C (61°F). Precipitation increases slightly to 7 mm (0.3 in), occurring over two days. The humidity also decreases to 64%, marking a transition towards the warmer months. For more detailed information, you can check out Ulan Bator weather in March.
December and April present stark contrasts in weather conditions. December is characterized by frigid temperatures, with average lows plummeting to -21°C (-5°F) and a maximum of only -3°C (28°F). The month experiences extremely low humidity at 89%, contributing to a bone-chilling atmosphere, and sees little precipitation, with no rainy days. In comparison, April brings a significant warming trend, where temperatures can dip to -16°C (4°F) but can rise to a comfortable maximum of 25°C (77°F). The average temperature hovers around 2°C (36°F), and the humidity drops to a more moderate 59%. Additionally, April sees around 15 mm (0.6 inches) of precipitation over four rainy days, making it a much wetter month. For more detailed information, check out Ulan Bator weather in April.
In December, Ulan Bator experiences frigid temperatures, with averages plunging to around -21°C (-5°F) and maximums barely reaching -3°C (28°F). The month sees little precipitation, with total rainfall measuring only 3 mm and an impressive 100% chance of dry days, while humidity remains high at 89%. In stark contrast, May brings a notable warming trend, with temperatures ranging from a minimum of -8°C (18°F) to a maximum of 30°C (87°F), resulting in an average of 9°C (48°F). Additionally, May experiences more precipitation, totaling 26 mm over five days, and a more comfortable humidity level of 50%. For a closer look at the conditions during this vibrant spring month, visit Ulan Bator weather in May.
December and June present strikingly contrasting weather patterns. In December, temperatures can plummet to a minimum of -39°C (-38°F) with an average of -21°C (-5°F) and a maximum reaching just -3°C (28°F). The month typically experiences very little precipitation, with only 3 mm (0.1 in) recorded over the entire month and an average humidity of 89%, creating a frigid and dry atmosphere. In stark contrast, June offers a more pleasant climate, with temperatures ranging from a minimum of -3°C (28°F) to a maximum of 32°C (90°F) and an average temperature of 15°C (59°F). This summer month brings significantly more moisture, with 44 mm (1.7 in) of precipitation over about 7 days and a lower humidity level of 55%. For a detailed look at the climate during this vibrant month, visit Ulan Bator weather in June.
December and July present starkly contrasting weather conditions. In December, Ulan Bator experiences frigid temperatures, with a minimum of -39°C (-38°F) and an average of -21°C (-5°F), reaching a maximum of only -3°C (28°F). Precipitation is minimal, with just 3 mm (0.1 in) across the month and high humidity at 89%. In contrast, July showcases a much milder climate, where temperatures range from a minimum of 5°C (41°F) to a maximum of 32°C (91°F), averaging around 17°C (64°F). This month also brings increased rainfall, totaling 72 mm (2.9 in) over 12 days and lower humidity at 57%. For a closer look at the summer weather, check out Ulan Bator weather in July.
The weather in December is characterized by extreme cold, with temperatures plummeting to a minimum of -39°C (-38°F) and averaging around -21°C (-5°F). This bitter chill is accompanied by high humidity at 89%, although precipitation is minimal at just 3 mm (0.1 in) over the month. In stark contrast, August experiences a much milder climate, where temperatures range from a minimum of 0°C (33°F) to a pleasant maximum of 28°C (82°F) and an average of 14°C (58°F). August also sees significantly more rainfall, totaling 83 mm (3.3 in) across about 13 days, paired with a lower humidity of 58%. For more specifics on August weather, you can check out Ulan Bator weather in August.
The weather in December contrasts sharply with that in September, reflecting the transition from late autumn to deep winter. December experiences frigid temperatures, with averages around -21°C (-5°F) and maximums barely reaching -3°C (28°F), coupled with high humidity at 89%. In stark contrast, September offers milder conditions, featuring a significant range in temperatures from a low of -9°C (16°F) to a pleasant high of 27°C (81°F). Additionally, September is characterized by increased precipitation of 51 mm (2.0 in) over 8 days, compared to December's minimal precipitation of only 3 mm (0.1 in) over a dry month. For those interested in exploring September’s climate in more detail, you can refer to Ulan Bator weather in September.
When comparing the weather in December and October, one can observe significant differences in temperature and precipitation. December is characterized by extreme cold, with average temperatures plummeting to -21°C (-5°F) and minimums even reaching -39°C (-38°F). In stark contrast, October offers much milder conditions, with an average temperature of -1°C (30°F) and maximums soaring up to 22°C (72°F). Additionally, October experiences more precipitation, totaling 21 mm (0.8 in) over four days, whereas December is exceptionally dry with just 3 mm (0.1 in) of precipitation and no rainy days. Humidity also varies considerably, as December maintains a high humidity level of 89%, compared to October's more moderate 65%. For more details, check out the Ulan Bator weather in October.
December weather in Ulan Bator is significantly colder than in November, with temperatures dropping to a minimum of -39°C (-38°F) and an average of -21°C (-5°F), compared to November's milder minimum of -35°C (-32°F) and an average of -12°C (11°F). While November experiences a maximum temperature of 9°C (49°F), December's highest recorded temperature is just -3°C (28°F). Additionally, December sees less precipitation, with only 3 mm (0.1 in) over a month of low humidity at 89%, whereas November has 10 mm (0.4 in) of precipitation occurring on two days, along with a more moderate humidity level of 67%. For more detailed insights, you can refer to Ulan Bator weather in November.
December in Ulan Bator presents a striking contrast to the milder months of the year, as bitter cold dominates the landscape. With consistently low temperatures, residents experience an average chill that often plummets to minimums well below freezing, creating a harsh yet serene winter atmosphere. Unlike other months, December sees virtually no precipitation, contributing to the crisp clarity of the air, while humidity levels remain high, giving it a unique feel amidst the cold. This stark winter scenery invites exploration of the region's beauty, making it an unforgettable experience. For a deeper understanding of the climate variations throughout the year, visit Ulan Bator Climate.