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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 0°C (32°F), with the minimum dipping to a chilly -22°C (-7°F) and the maximum reaching a pleasant 19°C (66°F). Expect 53 mm (2.1 in) of precipitation spread over about 7 days, while humidity levels average a notable 81%.

December Temperature in Union

In December in Union, the average temperature is 0°C (32°F), with maximums reaching 19°C (66°F) and minimums dropping as low as -22°C (-7°F). Travelers should be prepared for chilly conditions, but can also enjoy some milder days suitable for outdoor exploration.

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 0°C (32°F), with highs reaching up to 19°C (66°F) and lows dropping to around -22°C (-7°F).
JanFebMarAprMayJunJulAugSepOctNovDec232538476071757266533731
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 total precipitation amount is 53 mm (2.1 in) spread over a period of 7 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 53 mm (2.1 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec6159721121621199292991215153
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 81%. With an average temperature of 0°C (32°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities less enjoyable and requiring extra layers to stay warm and dry while traveling.

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 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
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 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Union, you can visit Hourly UV Index in Union.

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 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098532
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-5°C (23°F)61 mm (2.4 inches)85%moderate
February Weather-4°C (26°F)59 mm (2.3 inches)85%moderate
March Weather3°C (38°F)72 mm (2.8 inches)85%high
April Weather8°C (47°F)112 mm (4.4 inches)85%very high
May Weather15°C (60°F)162 mm (6.4 inches)78%very high
June Weather21°C (71°F)119 mm (4.7 inches)80%very high
July Weather24°C (75°F)92 mm (3.6 inches)78%very high
August Weather22°C (72°F)92 mm (3.6 inches)76%very high
September Weather19°C (67°F)99 mm (3.9 inches)79%very high
October Weather11°C (53°F)121 mm (4.8 inches)83%moderate
November Weather3°C (38°F)51 mm (2.0 inches)88%moderate
December Weather0°C (32°F)53 mm (2.1 inches)81%low

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