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December Weather in Hyannis, United States

Last updated: June 24, 2025

In December, the average temperature in Hyannis, United States hovers around -1°C (30°F), with extremes dipping as low as -24°C (-12°F) and occasionally reaching up to 22°C (72°F). Expect a total precipitation of about 21 mm (0.8 in) spread over 4 days, coupled with an average humidity level of 78%. Stay prepared!

December Temperature in Hyannis

In December in Hyannis, the average temperature is -1°C (30°F). Maximum temperatures can reach 22°C (72°F), while minimums can drop as low as -24°C (-12°F). Be sure to pack accordingly to enjoy your trip, as the weather can vary dramatically.

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

The chart illustrates December temperature patterns in Hyannis, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hyannis, December typically has an average temperature of -1°C (30°F), with highs reaching up to 22°C (72°F) and lows dropping to around -24°C (-12°F).
JanFebMarAprMayJunJulAugSepOctNovDec272437445569747164463830
Data source: Temperature data for Hyannis 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 Hyannis

In Hyannis in December, the precipitation amount is 21 mm (0.8 in) over a span of 4 days.

December Precipitation Trends in Hyannis

The chart displays monthly precipitation patterns in Hyannis, 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 Hyannis, December typically receives around 21 mm (0.8 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec1424634913656635846362221
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Hyannis

In Hyannis in December humidity is 78%. With an average temperature of -1°C (30°F), this humidity feels like a biting chill that seeps into your bones, making traveling outdoors a brisk challenge.

December Average Humidity in Hyannis

This chart illustrates the average monthly humidity levels in Hyannis, 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 Hyannis is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec73%80%64%64%76%79%77%79%70%64%75%78%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Hyannis

In Hyannis 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 Hyannis, you can check the information here.

Maximum UV Index Levels in Hyannis for December

The chart shows the monthly maximum UV Index (UVI) for Hyannis 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 Hyannis typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3568101111109643
Data source: Hyannis 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 Hyannis Compares to Other Months

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

This table compares monthly weather conditions in Hyannis, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)14 mm (0.5 inches)73%moderate
February Weather-4°C (25°F)24 mm (0.9 inches)80%moderate
March Weather3°C (38°F)63 mm (2.5 inches)64%high
April Weather7°C (44°F)49 mm (1.9 inches)64%very high
May Weather13°C (55°F)136 mm (5.4 inches)76%very high
June Weather21°C (70°F)56 mm (2.2 inches)79%extreme
July Weather23°C (74°F)63 mm (2.5 inches)77%extreme
August Weather21°C (71°F)58 mm (2.3 inches)79%very high
September Weather18°C (65°F)46 mm (1.8 inches)70%very high
October Weather8°C (46°F)36 mm (1.4 inches)64%high
November Weather3°C (38°F)22 mm (0.9 inches)75%moderate
December Weather-1°C (30°F)21 mm (0.8 inches)78%moderate

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