Last updated: August 21, 2025
In December, weather conditions in the USA and Japan present a diverse array of experiences. Temperatures range from a maximum of 21°C (71°F) during warmer days to a chilly minimum of -1°C (31°F) at night, with an average of 8°C (46°F) that suits the season. The month sees significant precipitation, totaling 59 mm (2.3 in) over an average of 8 days, contributing to a humidity level of 79% that envelops the atmosphere. This combination of temperatures and moisture creates a unique and dynamic winter climate, perfect for both seasonal festivities and outdoor adventures.
In December, temperatures in the USA begin to reflect the chill of winter, with minimums dipping to -1°C (31°F) and averages hovering around 8°C (46°F). This marks a noticeable drop from the milder fall months, signaling the transition into colder weather. The highs can still reach a comfortable 21°C (71°F), especially in southern regions, offering a brief respite from the cold. Conversely, Japan experiences more moderate conditions, with December temperatures ranging from lows of -4°C (25°F) to highs of 20°C (68°F), showcasing a gradual cooling trend that mirrors the northern hemisphere's seasonal shift. Overall, the month serves as a bridge to winter, with temperatures steadily declining as the year draws to a close.
In December, precipitation in the USA sees a modest amount of 59 mm (2.3 in), occurring over about 8 days of the month. This represents a slight uptick compared to November's 47 mm (1.9 in), indicating a trend of increasing rainfall as winter deepens. As the year winds down, precipitation generally becomes less frequent, peaking earlier in the year during the summer months, specifically July with a hefty 329 mm (13.0 in) spread over 19 days. The gradual retreat in rainfall after July is evident, reflecting the seasonal shift, but December offers just enough rain to wrap up the year with a touch of moisture before the drier months ahead.
As December rolls in, humidity levels in the USA show a slight decline from previous months, settling at 79%. This decrease follows a steady rise throughout the summer, where July peaked at an impressive 92%, making it the most humid month of the year. Interestingly, the winter months typically start with lower humidity, but December's figures suggest a return to more moderate conditions after the summer's peak. Japan mirrors this trend, where humidity tends to fluctuate with the seasons, often following similar patterns of rising during the summer and tapering as winter approaches. Overall, December acts as a transitional month in both regions, marking the shift towards drier air as the colder months set in.
In December, both the USA and Japan experience a notable decline in UV Index levels, dropping to 4, categorized as moderate. This marks a significant shift from the extreme readings seen in the summer months, which can peak at 12. With a burn time of 30 minutes in December, individuals can enjoy outdoor activities with comparatively less risk of sunburn. This trend highlights the seasonal variations in UV exposure, reminding us that winter months offer a safer window for sun exposure. As temperatures cool and UV Index levels decrease, it's essential to stay informed about these changes. For more details, check the Usa UV Index.
UV Risk Categories
As the year draws to a close, December brings a modest 217 hours of sunshine, marking a slight dip from the vibrant bask of the summer months, particularly August, which shines brightly with 297 hours. The transition from the warmth of April's 276 hours to the cooler December underscores the seasonal shift, with spring peaking before the gradual decrease leading into winter. While daylight wanes in December, it still offers more sun than the earlier months of the year, such as January, with its mere 172 hours. Overall, the trend highlights a gradual ascent in sunshine hours from winter's low in January, peaking mid-year before settling comfortably in the colder season, making December's sunshine a gentle reminder of the warmth that has passed.
As we look at the likelihood of sunny weather in December in the USA and Japan, there's a notable trend of increasing sunshine compared to the earlier months in the year. December brings a 51% chance of sun, significantly higher than the summer months of June and July, which plummet to 23% and 20%, respectively. This trend suggests a shift away from the typically overcast skies that characterize the middle of the year, moving toward a more optimistic outlook as the year wraps up. Furthermore, December's chances are closely aligned with the sunnier autumn month of November at 53%, indicating a gradual transition into more favorable winter conditions. Thus, for those dreaming of a bright December, there's a reasonable probability that the sun will shine upon their festivities.
As December rolls in, both the USA and Japan experience a notable dip in daylight hours, with the sun gracing these regions for only 9 hours a day. This decline is part of a broader seasonal trend, as daylight gradually increases from January through July, peaking at 14 hours during the summer months. Following this high point, daylight diminishes through the fall, ultimately leading to the shorter days of winter. This rhythmic cycle showcases the changing seasons and highlights the contrast between the vibrant summer days and the subdued winter months, inviting a reflective appreciation for the natural ebb and flow of light throughout the year.
As December rolls in, the wind speeds across both the USA and Japan pick up slightly, averaging 3.3 m/s (7 mph)—a refreshing change compared to the summer months where winds slacken to around 2.2 m/s (5 mph). This upward trend signifies a transition from the calmer days of late summer and fall, where wind speeds hovered between 2.2 m/s and 2.8 m/s. Notably, December offers a briskness reminiscent of early winter, bridging the gap toward higher wind speeds seen in the early months of the year, such as January's 3.0 m/s. This seasonal cycle paints a picture of the dynamic and changing nature of wind patterns, inviting us to embrace the chill and the energy it brings as the year draws to a close.
Weather in Usa varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Usa, focusing on differences in temperature, rainfall, humidity, and UV levels.
In December, the weather features a mild temperature range with a minimum of -1°C (31°F) and an average of 8°C (46°F), peaking at a maximum of 21°C (71°F). This month experiences approximately 59 mm (2.3 in) of precipitation over about 8 days, accompanied by relatively high humidity levels at 79%. In contrast, January sees slightly cooler temperatures, with a minimum of -4°C (25°F), an average of 6°C (42°F), and a maximum of 16°C (61°F). Rainfall is slightly lower at 52 mm (2.0 in) over just 6 days, and humidity decreases slightly to 75%. For more detailed weather information, you can check Usa weather in January.
In December, temperatures typically range from a chilly minimum of -1°C (31°F) to a comfortable maximum of 21°C (71°F), with an average of around 8°C (46°F). The month sees a decent amount of precipitation at 59 mm (2.3 in) over about 8 days, and humidity levels sit at 79%. In contrast, February tends to be slightly colder, with minimum temperatures dropping to -4°C (26°F) and an average of 6°C (44°F), while the maximum temperature remains close at 20°C (68°F). This month experiences a bit more precipitation, totaling 71 mm (2.8 in) over 10 days, and humidity is lower at 71%. For more detailed weather insights, check out Usa weather in February.
In December, temperatures range from a chilly minimum of -1°C (31°F) to a mild maximum of 21°C (71°F), with an average of 8°C (46°F). The month sees about 59 mm (2.3 in) of precipitation over 8 days, accompanied by relatively high humidity at 79%. In contrast, March offers slightly warmer weather, with minimums of 2°C (36°F) and an average of 11°C (51°F). The maximum remains the same at 21°C (71°F), but the month experiences increased precipitation at 122 mm (4.8 in) over 12 days, along with lower humidity at 71%. For more detailed weather insights, you can visit Usa weather in March.
In December, temperatures typically range from a minimum of -1°C (31°F) to a maximum of 21°C (71°F), with an average temperature of around 8°C (46°F). The month experiences 59 mm (2.3 in) of precipitation spread over 8 days, resulting in a humidity level of 79%.
In contrast, April is milder, with temperatures fluctuating between 5°C (41°F) and 25°C (78°F), and an average temperature of 15°C (59°F). This month sees increased precipitation, totaling 114 mm (4.5 in) over 9 days, while maintaining a slightly lower humidity level of 78%.
For more detailed insights into the weather trends during this period, visit Usa weather in April.
December and May showcase contrasting weather patterns. In December, temperatures range from a chilly minimum of -1°C (31°F) to a mild maximum of 21°C (71°F), with an average around 8°C (46°F). The month sees approximately 59 mm (2.3 in) of precipitation spread over 8 days, and the humidity hovers around 79%. In stark contrast, May experiences much warmer temperatures, with a minimum of 9°C (48°F) and a maximum that can reach up to 30°C (86°F), averaging 20°C (68°F). Precipitation increases to 156 mm (6.2 in) occurring over 11 days, accompanied by a slight rise in humidity to 84%. For more insights into weather trends, visit Usa weather in May.
December and June present stark contrasts in weather. In December, temperatures range from a minimum of -1°C (31°F) to a maximum of 21°C (71°F), with an average of 8°C (46°F). The month typically sees 59 mm (2.3 in) of precipitation over about 8 days and maintains a humidity level of 79%. In sharp contrast, June boasts much warmer temperatures, with minima around 16°C (61°F) and maxima reaching 31°C (87°F), averaging 23°C (74°F). This month experiences significantly higher precipitation at 194 mm (7.6 in) over 14 days and a humidity level that rises to 86%. For a more detailed understanding of weather patterns, you can check out Usa weather in June.
December and July present strikingly different weather patterns. In December, temperatures range from a chilly minimum of -1°C (31°F) to an average of 8°C (46°F), with maximum temperatures reaching 21°C (71°F). This month experiences moderate precipitation of 59 mm (2.3 in) over 8 days, accompanied by a humidity level of 79%. In contrast, July is markedly warmer, with minimum temperatures starting at 19°C (67°F) and averaging 27°C (80°F), peaking at 34°C (93°F). The month is characterized by heavy rainfall, accumulating 329 mm (13.0 in) over 19 days, and a higher humidity level of 92%. For a more detailed look at weather patterns in July, you can visit Usa weather in July.
December and August present distinctly different weather patterns. In December, temperatures range from a chilly minimum of -1°C (31°F) to a pleasant maximum of 21°C (71°F), with an average of about 8°C (46°F). The month experiences approximately 59 mm (2.3 in) of precipitation over 8 days and maintains a humidity level of 79%. In contrast, August is notably warmer, featuring a minimum temperature of 20°C (68°F) and an average high of 35°C (95°F), with an overall average of 28°C (83°F). This month also sees significantly more precipitation, totaling about 224 mm (8.8 in) over 14 days, while humidity rises to 91%. For more insights about weather conditions, check Usa weather in August.
In comparing the weather between December and September, a marked contrast emerges. December experiences cooler temperatures, ranging from a minimum of -1°C (31°F) to an average of 8°C (46°F), with a maximum reaching 21°C (71°F). It also tends to be relatively dry, with only 59 mm (2.3 in) of precipitation spread over 8 days, and humidity levels around 79%. In stark contrast, September is much warmer, with minimums of 16°C (62°F), an average of 24°C (76°F), and maximum temperatures peaking at 33°C (91°F). Additionally, September is significantly wetter, receiving 173 mm (6.8 in) of precipitation over 15 days, and it has slightly higher humidity at 84%. These differences highlight the seasonal changes that influence climate conditions in these months. For more detailed insights, check Usa weather in September.
In comparing the weather of October and December, October features milder temperatures, with a minimum of 10°C (50°F) and an average of 19°C (67°F), reaching up to 29°C (85°F) on warmer days. In contrast, December sees a drop in temperature, with a minimum of -1°C (31°F) and an average of 8°C (46°F), only peaking at 21°C (71°F). Additionally, October experiences significantly more rainfall, with 138 mm (5.4 in) over about 9 days, compared to December's 59 mm (2.3 in) spread across 8 days. Humidity levels are slightly higher in both months, with October at 83% and December at 79%. For more details, you can check out Usa weather in October.
In comparing the weather of December and November, December presents cooler temperatures, with a minimum of -1°C (31°F) and an average of 8°C (46°F), while November enjoys milder conditions, featuring a minimum of 4°C (40°F) and an average of 13°C (56°F). Additionally, November sees a higher maximum temperature of 26°C (79°F) compared to December's peak of 21°C (71°F). Precipitation levels are slightly higher in December at 59 mm (2.3 in) over 8 days, compared to November's 47 mm (1.9 in) over 6 days. Humidity remains relatively high in both months, with December at 79% and November slightly higher at 81%. For more detailed insights, you can check out Usa weather in November.
As December rolls in, the weather across the USA transforms, offering a unique blend of cool temperatures and enhanced humidity. With average temperatures settling around 8°C (46°F), December stands out from the warmer months, showcasing the crispness of winter. Unlike the drier periods earlier in the year, December experiences 8 days of precipitation, adding to the season's character with a total of about 59 mm (2.3 in) of rainfall. This month can bring a refreshing chill, making it a stark contrast to the balmy summer days. For those seeking to understand the broader climate details, check out Usa Climate for more insights into temperature and weather trends.