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December Weather in Old Saybrook, United States

Last updated: June 24, 2025

In Old Saybrook, United States, the average temperature in December hovers around 4°C (39°F). Expect chilly nights with a minimum temperature dipping to -11°C (12°F), while daytime highs can reach up to 16°C (61°F). Over the course of the month, precipitation averages 151 mm (6.0 in) spread across 11 days, contributing to a notably high average humidity of 80%.

December Temperature in Old Saybrook

In December in Old Saybrook, the average temperature is 4°C (39°F), with maximums reaching 16°C (61°F) and minimums dropping as low as -11°C (12°F). Travelers should be prepared for chilly conditions and pack warm clothing to fully enjoy their visit.

December Weather in Old Saybrook: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Old Saybrook, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Old Saybrook, December typically has an average temperature of 4°C (39°F), with highs reaching up to 16°C (61°F) and lows dropping to around -11°C (12°F).
JanFebMarAprMayJunJulAugSepOctNovDec343539475666737468604839
Data source: Temperature data for Old Saybrook 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 Old Saybrook

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

December Precipitation Trends in Old Saybrook

The chart displays monthly precipitation patterns in Old Saybrook, 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 Old Saybrook, December typically receives around 151 mm (6.0 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec83113105141119821289498151106151
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Old Saybrook

In Old Saybrook in December, humidity is 80%. With an average temperature of 4°C (39°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and requiring extra layers to stay warm while navigating through the misty streets.

December Average Humidity in Old Saybrook

This chart illustrates the average monthly humidity levels in Old Saybrook, 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 Old Saybrook is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Old Saybrook

In Old Saybrook 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 Old Saybrook, you can visit Hourly UV Index in Old Saybrook.

Maximum UV Index Levels in Old Saybrook for December

The chart shows the monthly maximum UV Index (UVI) for Old Saybrook 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 Old Saybrook typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35689101098642
Data source: Old Saybrook 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 Old Saybrook Compares to Other Months

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

This table compares monthly weather conditions in Old Saybrook, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)83 mm (3.3 inches)84%moderate
February Weather2°C (35°F)113 mm (4.4 inches)82%moderate
March Weather4°C (39°F)105 mm (4.1 inches)81%high
April Weather8°C (47°F)141 mm (5.5 inches)78%very high
May Weather13°C (56°F)119 mm (4.7 inches)69%very high
June Weather19°C (66°F)82 mm (3.2 inches)69%very high
July Weather23°C (74°F)128 mm (5.1 inches)62%very high
August Weather23°C (74°F)94 mm (3.7 inches)65%very high
September Weather20°C (69°F)98 mm (3.9 inches)68%very high
October Weather16°C (60°F)151 mm (5.9 inches)74%high
November Weather9°C (48°F)106 mm (4.2 inches)82%moderate
December Weather4°C (39°F)151 mm (6.0 inches)80%low

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