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December Weather in Bethesda, United States

Last updated: June 24, 2025

In Bethesda, United States, the average temperature in December hovers around 3°C (37°F). Expect minimum chills of -16°C (4°F) and occasional peaks of up to 18°C (65°F). This month brings about 114 mm (4.5 in) of precipitation spread across 12 days, contributing to an average humidity of 86%. Prepare for a cool and wet atmosphere!

December Temperature in Bethesda

In December in Bethesda, the average temperature is 3°C (37°F). The maximum can reach 18°C (65°F), while the minimum can drop as low as -16°C (4°F). Travelers should be prepared for a wide temperature range, bringing layered clothing to stay comfortable throughout their visit.

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

The chart illustrates December temperature patterns in Bethesda, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Bethesda, December typically has an average temperature of 3°C (37°F), with highs reaching up to 18°C (65°F) and lows dropping to around -16°C (4°F).
JanFebMarAprMayJunJulAugSepOctNovDec323643526370757368584337
Data source: Temperature data for Bethesda 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 Bethesda

In Bethesda in December, the precipitation amount is 114 mm (4.5 in) spread over 12 days.

December Precipitation Trends in Bethesda

The chart displays monthly precipitation patterns in Bethesda, 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 Bethesda, December typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec931211191421411651339511412092114
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Bethesda

In Bethesda in December humidity is 86%. With an average temperature of 3°C (37°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities uncomfortable and travel less enjoyable.

December Average Humidity in Bethesda

This chart illustrates the average monthly humidity levels in Bethesda, 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 Bethesda is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%88%87%82%84%82%73%74%81%89%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Bethesda

In Bethesda 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 Bethesda, you can check the information here.

Maximum UV Index Levels in Bethesda for December

The chart shows the monthly maximum UV Index (UVI) for Bethesda 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 Bethesda typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098643
Data source: Bethesda 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 Bethesda Compares to Other Months

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

This table compares monthly weather conditions in Bethesda, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)93 mm (3.7 inches)88%moderate
February Weather2°C (36°F)121 mm (4.8 inches)88%moderate
March Weather6°C (43°F)119 mm (4.7 inches)88%high
April Weather11°C (52°F)142 mm (5.6 inches)86%very high
May Weather17°C (63°F)141 mm (5.6 inches)82%very high
June Weather21°C (71°F)165 mm (6.5 inches)84%very high
July Weather24°C (75°F)133 mm (5.2 inches)82%very high
August Weather23°C (73°F)95 mm (3.7 inches)73%very high
September Weather20°C (68°F)114 mm (4.5 inches)73%very high
October Weather14°C (58°F)120 mm (4.7 inches)81%high
November Weather6°C (43°F)92 mm (3.6 inches)89%moderate
December Weather3°C (37°F)114 mm (4.5 inches)86%moderate

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