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December Weather in Potomac, United States

Last updated: June 24, 2025

In December, the average temperature in Potomac, United States hovers around 2°C (36°F). During this time, you can expect temperatures to range from a brisk -25°C (-12°F) at their lowest to a mild 18°C (65°F) at their peak. With an average precipitation of 59 mm (2.3 in) spread over 8 days, and a humidity level of 84%, be prepared for a chilly and damp month ahead!

December Temperature in Potomac

In December in Potomac, the average temperature is 2°C (36°F). Maximum temperatures can reach 18°C (65°F), while minimums can plummet to as low as -25°C (-12°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

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

The chart illustrates December temperature patterns in Potomac, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Potomac, 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 -25°C (-12°F).
JanFebMarAprMayJunJulAugSepOctNovDec283142526474777470574135
Data source: Temperature data for Potomac 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 Potomac

In Potomac in December, the total precipitation amount is 59 mm (2.3 in) spread over 8 days.

December Precipitation Trends in Potomac

The chart displays monthly precipitation patterns in Potomac, 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 Potomac, December typically receives around 59 mm (2.3 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec777711111814711287110761197459
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Potomac

In Potomac in December, humidity is 84%. With an average temperature of 2°C (36°F), this humidity feels like a cold, damp blanket wrapping around you, making outdoor activities less inviting and requiring extra layers to stay comfortable while traveling.

December Average Humidity in Potomac

This chart illustrates the average monthly humidity levels in Potomac, 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 Potomac is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%83%84%85%79%82%80%81%80%82%88%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Potomac

In Potomac 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 Potomac, you can visit Hourly UV Index in Potomac.

Maximum UV Index Levels in Potomac for December

The chart shows the monthly maximum UV Index (UVI) for Potomac 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 Potomac typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910111098642
Data source: Potomac 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 Potomac Compares to Other Months

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

This table compares monthly weather conditions in Potomac, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)77 mm (3.0 inches)82%moderate
February Weather-1°C (31°F)77 mm (3.0 inches)83%moderate
March Weather6°C (43°F)111 mm (4.4 inches)84%high
April Weather11°C (52°F)118 mm (4.6 inches)85%very high
May Weather18°C (65°F)147 mm (5.8 inches)79%very high
June Weather23°C (74°F)112 mm (4.4 inches)82%extreme
July Weather25°C (77°F)87 mm (3.4 inches)80%very high
August Weather23°C (74°F)110 mm (4.3 inches)81%very high
September Weather21°C (70°F)76 mm (3.0 inches)80%very high
October Weather14°C (57°F)119 mm (4.7 inches)82%high
November Weather5°C (41°F)74 mm (2.9 inches)88%moderate
December Weather2°C (36°F)59 mm (2.3 inches)84%low

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