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December Weather in Union, United States

Last updated: June 24, 2025

In December, the average temperature in Union, United States is a cool 11°C (52°F). While temperatures can dip to a chilly -4°C (25°F) or soar to a warm 27°C (80°F), visitors should be prepared for occasional rain, with an average precipitation of 121 mm (4.8 in) over 12 days. Additionally, the air tends to be quite humid, with an average humidity of 88%.

December Temperature in Union

In December in Union, the average temperature is 11°C (52°F). The maximum can reach 27°C (80°F), while the minimum can drop as low as -4°C (25°F). This varied climate makes Union an intriguing destination for travelers seeking both mild and cooler experiences.

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 11°C (52°F), with highs reaching up to 27°C (80°F) and lows dropping to around -4°C (25°F).
JanFebMarAprMayJunJulAugSepOctNovDec485460647379818178695551
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 reaches 121 mm (4.8 in) over the course of 12 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 121 mm (4.8 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec1051561161361221631211279610070121
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 88%. With an average temperature of 11°C (52°F), this humidity feels like a heavy blanket wrapping around you, making travel uncomfortable and the air feel thick, encouraging you to seek shelter or stay hydrated as you explore.

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 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%82%82%82%79%82%77%74%73%85%88%
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 reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Union for better planning.

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 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec478111111111110864
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 Weather9°C (48°F)105 mm (4.1 inches)85%moderate
February Weather12°C (54°F)156 mm (6.1 inches)84%high
March Weather16°C (60°F)116 mm (4.6 inches)82%very high
April Weather18°C (65°F)136 mm (5.4 inches)82%extreme
May Weather23°C (74°F)122 mm (4.8 inches)82%extreme
June Weather26°C (79°F)163 mm (6.4 inches)79%extreme
July Weather27°C (81°F)121 mm (4.8 inches)82%extreme
August Weather27°C (81°F)127 mm (5.0 inches)77%extreme
September Weather25°C (78°F)95 mm (3.8 inches)74%very high
October Weather20°C (69°F)100 mm (3.9 inches)73%very high
November Weather13°C (55°F)70 mm (2.7 inches)85%high
December Weather11°C (52°F)121 mm (4.8 inches)88%moderate

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