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January Weather in Belfast, United States

Last updated: June 24, 2025

In Belfast, United States, the average temperature for January hovers around -4°C (24°F), with extremes ranging from a chilly -27°C (-16°F) to a mild 16°C (61°F). Expect 78 mm (3.1 in) of precipitation spread over 13 days, accompanied by a high average humidity of 91%. Prepare for a brisk yet intriguing climate this month!

January Temperature in Belfast

In January in Belfast, the average temperature is -4°C (24°F), with maximums reaching 16°C (61°F) and minimums dropping as low as -27°C (-16°F). This chilly weather suggests that visitors should pack warm clothing and be prepared for a range of temperatures when traveling to Belfast during this time.

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

The chart illustrates January 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. In Belfast, January typically has an average temperature of -4°C (24°F), with highs reaching up to 16°C (61°F) and lows dropping to around -27°C (-16°F).
JanFebMarAprMayJunJulAugSepOctNovDec242734445665706862513730
Data source: Temperature data for Belfast generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Belfast

In Belfast in January, the precipitation amount is 78 mm (3.1 in) spread over 13 days.

January Precipitation Trends in Belfast

The chart displays monthly precipitation patterns in Belfast, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Belfast, January typically receives around 78 mm (3.1 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec7890801091179911884771278587
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Belfast

In Belfast in January humidity is 91%. With an average temperature of -4°C (24°F), this humidity feels like an icy grip that seeps into your bones, making travel uncomfortable and challenging as the cold air, mixed with high moisture, creates a biting chill that discourages outdoor exploration.

January Average Humidity in Belfast

This chart illustrates the average monthly humidity levels in Belfast, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Belfast is approximately 91%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%91%88%88%82%80%77%72%76%83%88%87%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Belfast

In Belfast in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Belfast, you can check the information here.

Maximum UV Index Levels in Belfast for January

The chart shows the monthly maximum UV Index (UVI) for Belfast in January, 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. In January, the maximum UV index in Belfast typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: Belfast January 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.

How January Weather in Belfast Compares to Other Months

Weather in Belfast varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Belfast, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Belfast, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (24°F)78 mm (3.1 inches)91%moderate
February Weather-3°C (27°F)90 mm (3.5 inches)91%moderate
March Weather1°C (34°F)80 mm (3.1 inches)88%high
April Weather7°C (45°F)109 mm (4.3 inches)88%very high
May Weather14°C (57°F)117 mm (4.6 inches)82%very high
June Weather18°C (65°F)99 mm (3.9 inches)79%very high
July Weather21°C (70°F)118 mm (4.7 inches)77%very high
August Weather20°C (68°F)84 mm (3.3 inches)72%very high
September Weather16°C (62°F)77 mm (3.0 inches)76%very high
October Weather11°C (52°F)127 mm (5.0 inches)83%high
November Weather3°C (37°F)85 mm (3.4 inches)88%moderate
December Weather-1°C (30°F)87 mm (3.4 inches)87%low

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