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December Weather in Riverhead, United States

Last updated: June 24, 2025

In December, the average temperature in Riverhead, United States hovers around 5°C (41°F), with a minimum that can dip as low as -10°C (15°F) and a maximum peaking at 17°C (62°F). Visitors can expect 137 mm (5.4 in) of precipitation spread over 11 days, contributing to an average humidity level of 80%.

December Temperature in Riverhead

In December in Riverhead, the average temperature is 5°C (41°F). Maximum temperatures can reach 17°C (62°F), while minimum temperatures can drop as low as -10°C (15°F). Travelers should be prepared for a wide range of weather conditions during this time.

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

The chart illustrates December temperature patterns in Riverhead, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Riverhead, December typically has an average temperature of 5°C (41°F), with highs reaching up to 17°C (62°F) and lows dropping to around -10°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec353640485768757569614941
Data source: Temperature data for Riverhead 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 Riverhead

In Riverhead in December, the total precipitation amount reaches 137 mm (5.4 in) over a span of 11 days.

December Precipitation Trends in Riverhead

The chart displays monthly precipitation patterns in Riverhead, 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 Riverhead, December typically receives around 137 mm (5.4 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec79106101126114761179689139100137
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Riverhead

In Riverhead in December humidity is 80%. With an average temperature of 5°C (41°F), this humidity feels like a damp chill that seeps into your bones, making outdoor exploration feel much colder than it actually is, leading to the necessity of layering up to stay comfortable while traveling.

December Average Humidity in Riverhead

This chart illustrates the average monthly humidity levels in Riverhead, 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 Riverhead 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 Riverhead

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

Maximum UV Index Levels in Riverhead for December

The chart shows the monthly maximum UV Index (UVI) for Riverhead 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 Riverhead typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3568910998642
Data source: Riverhead 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 Riverhead Compares to Other Months

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

This table compares monthly weather conditions in Riverhead, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (36°F)79 mm (3.1 inches)84%moderate
February Weather2°C (37°F)106 mm (4.2 inches)82%moderate
March Weather4°C (40°F)101 mm (4.0 inches)81%high
April Weather9°C (49°F)126 mm (5.0 inches)78%very high
May Weather14°C (58°F)114 mm (4.5 inches)69%very high
June Weather20°C (68°F)76 mm (3.0 inches)69%very high
July Weather24°C (75°F)117 mm (4.6 inches)62%very high
August Weather24°C (75°F)96 mm (3.8 inches)65%very high
September Weather21°C (70°F)89 mm (3.5 inches)68%very high
October Weather16°C (61°F)139 mm (5.5 inches)74%high
November Weather9°C (49°F)100 mm (3.9 inches)82%moderate
December Weather5°C (41°F)137 mm (5.4 inches)80%low

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