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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 is a cool 5°C (42°F), with a minimum that can dip as low as -12°C (10°F) and a maximum peaking at 24°C (76°F). Expect an average humidity of 87%, making the air feel quite crisp, and be prepared for some precipitation, as there’s an average of 53 mm (2.1 in) spread over 7 days.

December Temperature in Mount Vernon

In December in Mount Vernon, the average temperature is 5°C (42°F). Maximums can reach 24°C (76°F) and minimums can drop as low as -12°C (10°F). Be prepared for a wide range of temperatures and pack accordingly for your travels!

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 5°C (42°F), with highs reaching up to 24°C (76°F) and lows dropping to around -12°C (10°F).
JanFebMarAprMayJunJulAugSepOctNovDec363849556676797673594641
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 total precipitation amount is 53 mm (2.1 in) spread over a period of 7 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 53 mm (2.1 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec85871461581678785128581526753
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 87%. With an average temperature of 5°C (42°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities less enjoyable and travel less inviting as the air becomes heavy and oppressive.

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 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%78%76%78%83%83%78%68%64%70%83%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
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 Weather2°C (36°F)85 mm (3.3 inches)81%moderate
February Weather3°C (38°F)87 mm (3.4 inches)78%high
March Weather10°C (50°F)146 mm (5.8 inches)76%high
April Weather13°C (56°F)158 mm (6.2 inches)78%very high
May Weather19°C (66°F)167 mm (6.6 inches)83%very high
June Weather24°C (76°F)87 mm (3.4 inches)83%extreme
July Weather26°C (79°F)85 mm (3.4 inches)78%extreme
August Weather25°C (77°F)128 mm (5.0 inches)68%very high
September Weather23°C (73°F)58 mm (2.3 inches)64%very high
October Weather15°C (59°F)152 mm (6.0 inches)70%high
November Weather8°C (47°F)67 mm (2.6 inches)83%moderate
December Weather5°C (42°F)53 mm (2.1 inches)87%moderate

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