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December Weather in Union, United States

Last updated: June 24, 2025

In December, the average temperature in Union, United States hovers around 2°C (36°F). Be prepared for a chilly range, as temperatures can dip as low as -18°C (0°F) and soar up to 18°C (65°F). During this time, expect approximately 87 mm (3.4 in) of precipitation over about 10 days, all while the air remains notably humid with an average of 87% humidity.

December Temperature in Union

In December in Union, the average temperature is 2°C (36°F), with maximums reaching up to 18°C (65°F) and minimums plunging as low as -18°C (0°F). Travelers should be prepared for a wide range of temperatures and pack accordingly for both mild days and cold nights.

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

The chart illustrates December temperature patterns in Union, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Union, December typically has an average temperature of 2°C (36°F), with highs reaching up to 18°C (65°F) and lows dropping to around -18°C (0°F).
JanFebMarAprMayJunJulAugSepOctNovDec303442526472767469574236
Data source: Temperature data for Union 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.

December Precipitation in Union

In Union in December, the precipitation amount is 87 mm (3.4 in) over the course of 10 days.

December Precipitation Trends in Union

The chart displays monthly precipitation patterns in Union, 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. In Union, December typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec7297106981291201009086999487
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Union

In Union in December, humidity is 87%. With an average temperature of 2°C (36°F), this humidity feels like an unwelcome chill that seeps into your bones, making outdoor exploration feel damp and heavy, and encouraging travelers to seek the warmth of indoor attractions instead.

December Average Humidity in Union

This chart illustrates the average monthly humidity levels in Union, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Union is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%87%85%81%82%81%73%73%78%89%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Union

In Union in December, 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 Union, you can check the information here.

Maximum UV Index Levels in Union for December

The chart shows the monthly maximum UV Index (UVI) for Union 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. In December, the maximum UV index in Union typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098643
Data source: Union 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.

How December Weather in Union Compares to Other Months

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

This table compares monthly weather conditions in Union, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (31°F)72 mm (2.8 inches)88%moderate
February Weather1°C (34°F)97 mm (3.8 inches)88%moderate
March Weather6°C (42°F)106 mm (4.2 inches)87%high
April Weather11°C (52°F)98 mm (3.9 inches)85%very high
May Weather18°C (64°F)129 mm (5.1 inches)81%very high
June Weather22°C (72°F)120 mm (4.7 inches)82%very high
July Weather24°C (76°F)100 mm (3.9 inches)81%very high
August Weather23°C (74°F)90 mm (3.5 inches)73%very high
September Weather21°C (69°F)86 mm (3.4 inches)73%very high
October Weather14°C (58°F)99 mm (3.9 inches)78%high
November Weather5°C (42°F)94 mm (3.7 inches)89%moderate
December Weather2°C (36°F)87 mm (3.4 inches)87%moderate

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