December Weather in Port Jefferson Station, United States

Last updated: June 24, 2025

In December, the average temperature in Port Jefferson Station, United States hovers around 5°C (40°F). Expect chilly days with minimum temperatures dipping to -10°C (15°F), while the mercury can rise to a pleasant 17°C (62°F). Precipitation is notable, with around 140 mm (5.5 in) over 11 days, contributing to an average humidity of 80%. Make sure to pack accordingly!

December Temperature in Port Jefferson Station

In December in Port Jefferson Station, the average temperature is 5°C (40°F). Maximums can reach 17°C (62°F), while minimums can drop as low as -10°C (15°F). Be sure to pack layers to stay comfortable during your travels!

December Weather in Port Jefferson Station: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Port Jefferson Station, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Port Jefferson Station, December typically has an average temperature of 5°C (40°F), with highs reaching up to 17°C (62°F) and lows dropping to around -10°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec353640485868757569614840
Data source: Temperature data for Port Jefferson Station 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 Port Jefferson Station

In Port Jefferson Station in December, the total precipitation amount is 140 mm (5.5 in), occurring over a span of 11 days.

December Precipitation Trends in Port Jefferson Station

The chart displays monthly precipitation patterns in Port Jefferson Station, 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 Port Jefferson Station, December typically receives around 140 mm (5.5 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec801121041321198713110394143103140
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Port Jefferson Station

In Port Jefferson Station in December, humidity is 80%. With an average temperature of 5°C (40°F), this humidity feels like a damp chill settling on your skin, making travel uncomfortable and requiring extra layers to stay warm while navigating the cool, misty atmosphere.

December Average Humidity in Port Jefferson Station

This chart illustrates the average monthly humidity levels in Port Jefferson Station, 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 Port Jefferson Station 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 Port Jefferson Station

In Port Jefferson Station 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 Port Jefferson Station, you can visit Hourly UV Index in Port Jefferson Station.

Maximum UV Index Levels in Port Jefferson Station for December

The chart shows the monthly maximum UV Index (UVI) for Port Jefferson Station 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 Port Jefferson Station typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35681010998642
Data source: Port Jefferson Station 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 Port Jefferson Station Compares to Other Months

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

This table compares monthly weather conditions in Port Jefferson Station, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (35°F)80 mm (3.1 inches)84%moderate
February Weather2°C (36°F)112 mm (4.4 inches)82%moderate
March Weather4°C (40°F)104 mm (4.1 inches)81%high
April Weather9°C (49°F)132 mm (5.2 inches)78%very high
May Weather14°C (58°F)119 mm (4.7 inches)69%very high
June Weather20°C (68°F)87 mm (3.4 inches)69%very high
July Weather24°C (76°F)131 mm (5.2 inches)62%very high
August Weather24°C (75°F)103 mm (4.0 inches)65%very high
September Weather21°C (70°F)94 mm (3.7 inches)68%very high
October Weather16°C (61°F)143 mm (5.6 inches)74%high
November Weather9°C (49°F)103 mm (4.0 inches)82%moderate
December Weather5°C (40°F)140 mm (5.5 inches)80%low

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