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December Weather in Mount Vernon, United States

Last updated: June 24, 2025

In December, the average temperature in Mount Vernon, United States hovers around 6°C (43°F). Expect a chilly minimum of -12°C (10°F), while the mercury can rise as high as 22°C (71°F). With 139 mm (5.5 in) of precipitation over 11 days, you might want to keep an umbrella handy! The climate also features a notable average humidity of 88%, making it feel quite damp. Prepare accordingly!

December Temperature in Mount Vernon

In December, in Mount Vernon, the average temperature is 6°C (43°F), with maximums reaching up to 22°C (71°F) and minimums dropping as low as -12°C (10°F). Be prepared for a wide range of temperatures and pack accordingly for your trip!

December Weather in Mount Vernon: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Mount Vernon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mount Vernon, December typically has an average temperature of 6°C (43°F), with highs reaching up to 22°C (71°F) and lows dropping to around -12°C (10°F).
JanFebMarAprMayJunJulAugSepOctNovDec374349576773787671614642
Data source: Temperature data for Mount Vernon 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 Mount Vernon

In Mount Vernon in December, the precipitation amount is 139 mm (5.5 in) occurring over a span of 11 days.

December Precipitation Trends in Mount Vernon

The chart displays monthly precipitation patterns in Mount Vernon, 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 Mount Vernon, December typically receives around 139 mm (5.5 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec9918213913512814910511712111880139
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Mount Vernon

In Mount Vernon in December, humidity is 88%. With an average temperature of 6°C (43°F), this humidity feels like a damp chill that seeps into your bones, making traveling uncomfortable and prompting you to seek warm shelter frequently.

December Average Humidity in Mount Vernon

This chart illustrates the average monthly humidity levels in Mount Vernon, 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 Mount Vernon is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%87%84%84%83%79%66%67%76%89%88%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Mount Vernon

In Mount Vernon 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 Mount Vernon, you can check the information here.

Maximum UV Index Levels in Mount Vernon for December

The chart shows the monthly maximum UV Index (UVI) for Mount Vernon 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 Mount Vernon typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3679111111109753
Data source: Mount Vernon 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 Mount Vernon Compares to Other Months

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

This table compares monthly weather conditions in Mount Vernon, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)99 mm (3.9 inches)88%moderate
February Weather6°C (43°F)182 mm (7.2 inches)88%high
March Weather10°C (49°F)139 mm (5.5 inches)87%high
April Weather14°C (57°F)135 mm (5.3 inches)84%very high
May Weather20°C (68°F)128 mm (5.0 inches)84%extreme
June Weather23°C (73°F)148 mm (5.8 inches)83%extreme
July Weather25°C (78°F)105 mm (4.1 inches)79%extreme
August Weather24°C (76°F)117 mm (4.6 inches)66%very high
September Weather22°C (72°F)121 mm (4.7 inches)67%very high
October Weather16°C (61°F)118 mm (4.6 inches)76%high
November Weather8°C (46°F)80 mm (3.1 inches)89%moderate
December Weather6°C (43°F)139 mm (5.5 inches)88%moderate

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