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December Weather in Watertown, United States

Last updated: June 24, 2025

In Watertown, United States, the average temperature in December hovers around 8°C (46°F). Expect chilly days, with minimums plunging to -9°C (15°F) and maximums reaching a pleasant 23°C (74°F). Rain is also common, with 151 mm (6.0 in) of precipitation spread across 11 days. The air can feel quite damp, with an average humidity of 88%.

December Temperature in Watertown

In December in Watertown, the average temperature is 8°C (46°F), with maximums reaching 23°C (74°F) and minimums dipping as low as -9°C (15°F). This varied climate makes it essential to pack layers for your travels to Watertown during this month.

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

The chart illustrates December temperature patterns in Watertown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Watertown, December typically has an average temperature of 8°C (46°F), with highs reaching up to 23°C (74°F) and lows dropping to around -9°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec414653597076807874634946
Data source: Temperature data for Watertown 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 Watertown

In Watertown in December, the precipitation amount reaches 151 mm (6.0 in) over a span of 11 days.

December Precipitation Trends in Watertown

The chart displays monthly precipitation patterns in Watertown, 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 Watertown, December typically receives around 151 mm (6.0 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec10919017615112314913112413014081152
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Watertown

In Watertown in December, humidity is 88%. With an average temperature of 8°C (46°F), this humidity feels like a damp chill that seeps into your bones, making outdoor exploration feel much more uncomfortable than the temperature alone would suggest.

December Average Humidity in Watertown

This chart illustrates the average monthly humidity levels in Watertown, 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 Watertown is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Watertown

In Watertown 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 Watertown, you can check the information here.

Maximum UV Index Levels in Watertown for December

The chart shows the monthly maximum UV Index (UVI) for Watertown 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 Watertown typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
Data source: Watertown 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 Watertown Compares to Other Months

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

This table compares monthly weather conditions in Watertown, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (41°F)109 mm (4.3 inches)87%moderate
February Weather8°C (46°F)190 mm (7.5 inches)87%high
March Weather12°C (53°F)176 mm (6.9 inches)85%high
April Weather15°C (60°F)151 mm (5.9 inches)82%very high
May Weather21°C (70°F)123 mm (4.8 inches)83%very high
June Weather25°C (76°F)149 mm (5.9 inches)82%extreme
July Weather26°C (80°F)131 mm (5.1 inches)78%extreme
August Weather25°C (78°F)124 mm (4.9 inches)67%very high
September Weather23°C (74°F)130 mm (5.1 inches)64%very high
October Weather17°C (64°F)140 mm (5.5 inches)74%high
November Weather9°C (49°F)81 mm (3.2 inches)87%moderate
December Weather8°C (46°F)151 mm (6.0 inches)88%moderate

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