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December Weather in Williamstown, United States

Last updated: June 24, 2025

In December, the average temperature in Williamstown, United States hovers around 4°C (40°F). However, temperatures can swing dramatically, with minimums dipping to -14°C (7°F) and maximums reaching a pleasant 20°C (68°F). During this month, expect about 116 mm (4.6 in) of precipitation spread over 11 days, contributing to a high average humidity of 87%.

December Temperature in Williamstown

In December in Williamstown, the average temperature is 4°C (40°F). Maximums can reach 20°C (68°F), while minimums can drop as low as -14°C (7°F). Be prepared for a wide range of temperatures when traveling during this time.

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

The chart illustrates December temperature patterns in Williamstown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Williamstown, December typically has an average temperature of 4°C (40°F), with highs reaching up to 20°C (68°F) and lows dropping to around -14°C (7°F).
JanFebMarAprMayJunJulAugSepOctNovDec343846556673777570594439
Data source: Temperature data for Williamstown 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 Williamstown

In Williamstown in December, the precipitation amount is 116 mm (4.6 in) over the course of 11 days.

December Precipitation Trends in Williamstown

The chart displays monthly precipitation patterns in Williamstown, 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 Williamstown, December typically receives around 116 mm (4.6 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec821231331351311681198810710491116
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Williamstown

In Williamstown in December humidity is 87%. With an average temperature of 4°C (40°F), this humidity feels like an uncomfortable chill that seeps into your bones, making it essential to dress warmly and prepare for damp conditions, which can dampen your spirits while traveling.

December Average Humidity in Williamstown

This chart illustrates the average monthly humidity levels in Williamstown, 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 Williamstown is approximately 87%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%87%85%81%82%81%73%73%78%89%87%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Williamstown

In Williamstown 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 Williamstown, you can check the information here.

Maximum UV Index Levels in Williamstown for December

The chart shows the monthly maximum UV Index (UVI) for Williamstown 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 Williamstown typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098643
Data source: Williamstown 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 Williamstown Compares to Other Months

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

This table compares monthly weather conditions in Williamstown, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (35°F)82 mm (3.2 inches)88%moderate
February Weather4°C (39°F)122 mm (4.8 inches)88%moderate
March Weather8°C (46°F)133 mm (5.2 inches)87%high
April Weather13°C (55°F)135 mm (5.3 inches)85%very high
May Weather19°C (66°F)131 mm (5.2 inches)81%very high
June Weather23°C (73°F)167 mm (6.6 inches)82%very high
July Weather25°C (77°F)119 mm (4.7 inches)81%very high
August Weather24°C (75°F)88 mm (3.5 inches)73%very high
September Weather21°C (71°F)107 mm (4.2 inches)73%very high
October Weather15°C (60°F)104 mm (4.1 inches)78%high
November Weather7°C (45°F)91 mm (3.6 inches)89%moderate
December Weather4°C (40°F)116 mm (4.6 inches)87%moderate

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