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December Weather in Somerville, United States

Last updated: June 24, 2025

In December, the average temperature in Somerville, United States hovers around 2°C (35°F). Expect chilly conditions, with minimums potentially dipping to -18°C (0°F) and maximums reaching up to 16°C (62°F). Rainfall is notable, with an average precipitation of 129 mm (5.1 in) spread over about 10 days. Don't forget your umbrella, as the average humidity is a high 81%, adding to the cool, damp atmosphere.

December Temperature in Somerville

In December in Somerville, the average temperature is 2°C (35°F). Maximums can reach 16°C (62°F) and minimums can be as low as -18°C (0°F). Make sure to pack warm clothing and be prepared for sudden temperature changes when traveling during this month.

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

The chart illustrates December temperature patterns in Somerville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Somerville, December typically has an average temperature of 2°C (35°F), with highs reaching up to 16°C (62°F) and lows dropping to around -18°C (0°F).
JanFebMarAprMayJunJulAugSepOctNovDec313337475766727266564435
Data source: Temperature data for Somerville 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 Somerville

In Somerville in December, the precipitation amount is 129 mm (5.1 in) over a span of 10 days.

December Precipitation Trends in Somerville

The chart displays monthly precipitation patterns in Somerville, 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 Somerville, December typically receives around 129 mm (5.1 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec77969614191871167284146101129
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Somerville

In Somerville in December humidity is 81%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill wrapping around you, making outdoor exploration quite uncomfortable and prompting you to seek warmth indoors rather than traveling extensively outside.

December Average Humidity in Somerville

This chart illustrates the average monthly humidity levels in Somerville, 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 Somerville is approximately 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Somerville

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

Maximum UV Index Levels in Somerville for December

The chart shows the monthly maximum UV Index (UVI) for Somerville 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 Somerville typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3558910997642
Data source: Somerville 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 Somerville Compares to Other Months

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

This table compares monthly weather conditions in Somerville, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)77 mm (3.0 inches)86%moderate
February Weather1°C (33°F)96 mm (3.8 inches)84%moderate
March Weather3°C (38°F)96 mm (3.8 inches)82%moderate
April Weather8°C (47°F)141 mm (5.6 inches)80%very high
May Weather14°C (57°F)91 mm (3.6 inches)72%very high
June Weather19°C (66°F)87 mm (3.4 inches)72%very high
July Weather22°C (73°F)116 mm (4.6 inches)67%very high
August Weather22°C (73°F)72 mm (2.8 inches)66%very high
September Weather19°C (66°F)84 mm (3.3 inches)71%high
October Weather13°C (57°F)146 mm (5.8 inches)78%high
November Weather6°C (44°F)101 mm (4.0 inches)84%moderate
December Weather2°C (35°F)129 mm (5.1 inches)81%low

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