December Weather in Belfast, United Kingdom

Last updated: March 17, 2025

In Belfast, United Kingdom, December presents a cool and often damp climate, with average temperatures hovering around 6°C (44°F). Expect maximums reaching 13°C (56°F) and occasional chilly nights dropping to a brisk -1°C (30°F). The city experiences 15 rainy days throughout the month, contributing to a total precipitation of 91 mm (3.6 in), and maintaining a high humidity level of 86%. This blend of cool temperatures and regular rainfall creates a uniquely atmospheric backdrop, ideal for enjoying the city’s festive spirit.

December Temperature in Belfast

In December, temperatures in Belfast begin to dip as winter approaches, showcasing a minimum of -1°C (30°F) and an average of 6°C (44°F). This trend reflects a gradual cooling from the milder temperatures of the preceding months, with the maximum reaching around 13°C (56°F). As the year winds down, the typical chill of December brings a cozy atmosphere, inviting locals and visitors alike to embrace the festive spirit of the season. Though the average remains stable compared to previous months, the noticeable drop in minimum temperatures hints at the winter chill to come, marking a transition that is characteristic of Belfast's December climate.

December Weather in Belfast: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Belfast, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec424344475257605956514744
Data source: Temperature data for Belfast generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Belfast

In December, Belfast experiences a notable precipitation total of 91 mm (3.6 in), contributing to a generally damp and moody atmosphere that characterizes the month. With 15 days of rainfall, December mirrors the trend of heightened precipitation seen in the preceding months, particularly November, which recorded an even higher total of 94 mm. This pattern reflects a gradual increase in rainfall through the autumn months and into winter, with December's precipitation sitting comfortably in the higher range for the year. As the city prepares for the festive season, the persistent rain creates a quintessentially atmospheric backdrop, with lush green landscapes contrasting against the gray skies, further enriching Belfast's unique charm.

December Precipitation Trends in Belfast

The chart displays monthly precipitation patterns in Belfast, with values for each month alongside December's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec6089804566788411575929491
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

December Humidity in Belfast

As December arrives in Belfast, the city's humidity levels remain relatively high at 86%, continuing a trend observed throughout the colder months. Following a gradual rise from 82% in May, humidity peaked at 90% in November, indicative of the city's damp and cool winter climate. Although December sees a slight decrease, the levels still mirror those of the preceding summer months, where humidity hovered around 86%. This consistent humidity not only contributes to the chill in the air but also sets the stage for the iconic moody atmosphere that defines Belfast during this time of year. Whether you’re enjoying a festive market or cozying up indoors, that omnipresent dampness encapsulates the essence of December in this vibrant city.

December Average Humidity in Belfast

This chart illustrates the average monthly humidity levels in Belfast, with December's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how December's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec87%86%86%85%82%84%86%86%88%89%90%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Belfast

In December, Belfast experiences a low UV Index of 1 with a typical burn time of 45 minutes, indicating minimal risk from sun exposure. This marks a return to the lowest levels of the year, a contrast to the higher indices seen in the summer months, such as July's very high index of 8 and the moderate readings of March and April. As daylight hours shorten and temperatures drop, residents can enjoy outdoor activities with reduced concern for UV-related skin damage. Understanding these seasonal trends helps in planning safe and enjoyable winter outings. For more detailed information, you can visit the Belfast UV Index.

Maximum UV Index Levels in Belfast for December

The chart shows the monthly maximum UV Index (UVI) for Belfast in December, 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.
JanFebMarAprMayJunJulAugSepOctNovDec124578865321
Data source: Belfast December 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.

December Sunshine in Belfast

In Belfast, December typically sees a relatively modest 87 hours of sunshine, concluding the year with a stark contrast to the sunlit peaks of earlier months. The sunshine hours gradually increase from January’s dreary 81 hours, reaching a vibrant 403 hours in May, the month's peak. As the year progresses, the sunniest days tend to be concentrated in the late spring and summer months, exemplified by the consistent high from June to August, where sunshine hovers around the 390-hour mark. The light begins to dwindle as autumn arrives, dropping sharply in November to just 115 hours. December maintains this trend, reminding locals and visitors alike that while winter may bring shorter days, the allure of Belfast's charm remains undiminished, inviting exploration even under a cap of cloud cover.

Monthly Sunshine Duration in Belfast: December Highlighted

The December sunshine duration represents the total number of hours Belfast experiences direct sunlight during the month of December, excluding cloudy or obstructed periods. This chart compares the sunshine duration of December with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec81h150h209h322h403h394h399h349h295h232h115h87h
Data source: Belfast December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Belfast During December

In Belfast, December marks a significant decline in the likelihood of sunny weather, with only a 14% chance of sunshine illuminating the gray winter skies. This trend follows a generally low pattern during the latter months of the year, where the sun peeks out infrequently. Despite some variability in the preceding months—most notably April's 42% and May's 33%—the colder seasons, from October to December, showcase a disheartening consistency in cloud cover. As the year wraps up, it becomes increasingly clear that anyone hoping for a bright winter day in Belfast may need to manage their expectations.

Percentage of Sunny Days in December in Belfast

The chart illustrates the percentage of sunny days in Belfast throughout the year, with December 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 Belfast experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec27%23%20%42%33%23%30%21%20%18%20%14%
Data source: Belfast December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Belfast in December

In Belfast, United Kingdom, the daylight duration experiences a fascinating rhythm throughout the year. Starting from a modest 7 hours in December, the days gradually lengthen, peaking at an impressive 17 hours in June. As winter gives way to spring, daylight steadily increases, illuminating 11 hours in March and reaching 14 hours by April. Following the zenith of summer, the daylight begins to recede, tapering down to 14 hours in August and returning to 7 hours by December. This cyclical pattern highlights a blend of seasonal change and the natural beauty of long summer days interspersed with the shorter, cozy winter hours.

Average Daylight Hours in Belfast for December

The chart illustrates the variation in daylight duration in Belfast throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec7h 56m9h 44m11h 54m14h 7m16h 5m17h 7m16h 34m14h 47m12h 38m10h 26m8h 27m7h 21m
Data source: Belfast daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Belfast

As December settles over Belfast, the wind carries a briskness that resonates with the sharp chill of winter. With an average wind speed of 4.9 m/s (11 mph), December's gales are reminiscent of the previous month, where winds reached 5.0 m/s (11 mph) in November. This slight dip in wind speed, contrasting with the sharper breezes seen in early winter months like February's 6.2 m/s (14 mph), underscores a trend towards calmer conditions. Interestingly, the overall pattern reveals a gradual easing in wind strength from the twilight of summer, where winds were languid at 2.6 m/s (6 mph) in July, to this invigorating December bluster, making it a quintessentially Belfast winter experience. The interplay of cold air masses and coastal influences consistently shapes the character of the city's winter winds, inviting both residents and visitors to embrace the season’s refreshing embrace.

Average December Wind Speed in Belfast

The chart displays monthly wind speed patterns in Belfast, with values for each month shown alongside December's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how December's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec4.36.24.83.53.93.82.63.23.44.75.04.9 m/s
Data source: Belfast December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Belfast Compares to Other Months

The weather in Belfast changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Belfast and find detailed weather information for every month.

In December, the weather presents a milder temperature range with minimums around -1°C (30°F) and maximums hitting 13°C (56°F), while January experiences slightly cooler minimums of -4°C (26°F) yet similar maximums of 14°C (57°F). Precipitation is more frequent in December, totaling 91 mm (3.6 in) over about 15 days, compared to January's 60 mm (2.3 in) during just 10 days. Despite these differences, both months maintain high humidity levels, averaging around 86% in December and increasing slightly to 87% in January. For more details, you can explore Belfast weather in January.

Comparing the weather in December and February reveals some intriguing similarities and slight variations. Both months feature an average temperature of around 6°C (44°F) with maximums reaching up to 13°C (56°F). However, December tends to be slightly milder with a minimum temperature of -1°C (30°F), compared to February's minimum of -2°C (28°F). Precipitation levels are nearly identical, with December averaging 91 mm (3.6 in) over 15 days and February at 89 mm (3.5 in) across 14 days. Notably, humidity remains consistent at 86% for both months, contributing to the overall dampness experienced during this winter season. For more specifics, you can explore Belfast weather in February.

When comparing the weather in December and March, some notable differences emerge. December is characterized by slightly milder temperatures, with an average of 6°C (44°F) and a maximum of 13°C (56°F), while March sees an increase in the average temperature to 7°C (44°F) and a higher maximum of 16°C (60°F). Precipitation levels are somewhat similar, with December receiving 91 mm (3.6 in) over 15 days and March getting a bit less at 80 mm (3.2 in) over 16 days. Both months share a high humidity level of 86%, making for a damp atmosphere typical of winter and early spring. For a more detailed look at March's climate, you can visit Belfast weather in March.

In comparing the weather between December and April, we find notable differences in temperature and precipitation. December features cooler temperatures, with an average of 6°C (44°F) and maximums reaching only 13°C (56°F), while April sees a mild increase, with average temperatures rising to 8°C (47°F) and highs reaching 18°C (65°F). Precipitation is also more abundant in December, with 91 mm (3.6 in) falling over 15 days, compared to April's 45 mm (1.8 in) over just 10 days. Additionally, humidity levels remain fairly similar, hovering around 86% in December and slightly lower at 85% in April. For more details about the weather in April, check out Belfast weather in April.

December weather in Belfast tends to be quite chilly, with average temperatures ranging from a minimum of -1°C (30°F) to a maximum of 13°C (56°F). The month sees substantial precipitation, averaging 91 mm (3.6 in) over 15 days, and high humidity levels around 86%. In contrast, May brings a significant change, with average temperatures rising from a minimum of 1°C (34°F) to a pleasant maximum of 22°C (71°F). While May still experiences rainfall, the total is lower at 66 mm (2.6 in) across 13 days and slightly less humidity at 82%. For a closer look at the May weather specifics, check out Belfast weather in May.

When comparing December and June, the differences in weather are quite pronounced. December typically experiences cooler temperatures, with a minimum dipping to -1°C (30°F) and an average of 6°C (44°F), while June enjoys milder conditions, featuring a minimum of 6°C (43°F) and an average of 14°C (57°F). Precipitation in December is slightly higher, totaling 91 mm (3.6 in) over 15 days, compared to June's 78 mm (3.1 in) across 14 days. Humidity levels remain relatively high in both months, slightly higher in December at 86% compared to 84% in June. For more detailed information about the weather in June, check out Belfast weather in June.

In December, temperatures in the region can dip to a minimum of -1°C (30°F), with an average of 6°C (44°F) and a maximum of 13°C (56°F). The month sees about 91 mm (3.6 in) of precipitation over approximately 15 days, contributing to the high humidity levels of 86%. In contrast, July experiences more temperate weather, with minimum temperatures of 8°C (47°F) and an average of 15°C (60°F), reaching a maximum of 26°C (78°F). This summer month hosts slightly less precipitation at 84 mm (3.3 in) over around 14 days, while still maintaining the same humidity of 86%. For more detailed information, you can check Belfast weather in July.

December and August present contrasting weather patterns in terms of temperature and precipitation. In December, the temperatures range from a chilly -1°C (30°F) at night to a mild 13°C (56°F) during the day, with an average temperature of 6°C (44°F). This month also experiences around 91 mm (3.6 in) of precipitation over 15 days, contributing to a humid atmosphere with humidity levels at 86%.

In contrast, August is generally warmer, with temperatures ranging from a minimum of 8°C (46°F) to a comfortable maximum of 22°C (71°F), and an average temperature of 15°C (59°F). Precipitation is slightly higher at 115 mm (4.5 in) spread over 19 days, while humidity remains consistent at 86%. For more details, you can check Belfast weather in August. Overall, while December is defined by colder temperatures and frequent rainfall, August offers a warmer and more pleasant climate.

December and September present distinctly different weather patterns. In December, temperatures are cooler, with a minimum of -1°C (30°F) and an average around 6°C (44°F), peaking at 13°C (56°F). This month experiences 91 mm (3.6 in) of precipitation over about 15 days, paired with high humidity at 86%. In contrast, September boasts milder temperatures, ranging from a minimum of 4°C (39°F) to an average of 13°C (56°F) and a maximum of 21°C (71°F). It receives less precipitation at 75 mm (3.0 in), also over 15 days, and has slightly higher humidity at 88%. For more details, check out this link: Belfast weather in September.

When comparing the weather in October and December, there are notable differences in temperature and humidity. In October, temperatures range from a minimum of 1°C (35°F) to a maximum of 18°C (65°F), with an average of 11°C (52°F). In contrast, December sees cooler temperatures, with a minimum of -1°C (30°F) and a maximum of 13°C (56°F), averaging 6°C (44°F). Precipitation levels are similar in both months, with October receiving 92 mm (3.6 in) and December slightly less at 91 mm (3.6 in), though both months experience rain over around 15 days. Humidity is relatively high in both months, though December is slightly less humid at 86% compared to October’s 89%. For more details about October weather, you can check Belfast weather in October.

When comparing the weather in December to that of November, December tends to be slightly cooler, with average temperatures ranging from a minimum of -1°C (30°F) to a maximum of 13°C (56°F), compared to November’s range of 0°C (32°F) to 15°C (59°F). Precipitation levels are quite similar, with December receiving 91 mm (3.6 in) and November having 94 mm (3.7 in), both spread over 15 days. Humidity is slightly lower in December at 86%, while November experiences a higher humidity level of 90%. For a detailed look at November weather, you can refer to Belfast weather in November.

Compare Belfast's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in Belfast

As December settles over Belfast, the city's weather takes on a distinct character, marked by cooler temperatures and increased precipitation compared to other months. With daily highs peaking around 13°C and lows dipping to -1°C, it's a month that invites layers and warmth. The frequent rain—averaging 91 mm over 15 damp days—coupled with a high humidity level of 86%, creates a somewhat bleak yet cozy atmosphere. While the chill may deter some, the holiday spirit often breathes life into the city, making December a unique time to experience Belfast. For a deeper dive into the city's weather patterns, check out Belfast Climate.