December Weather in Hyannis, United States

Last updated: February 24, 2025

December in Hyannis, United States, brings a chilly atmosphere with temperatures ranging from a maximum of 15°C (60°F) to a brisk minimum of -12°C (11°F), averaging around 4°C (40°F). This month typically sees 12 days of precipitation, accumulating to about 136 mm (5.4 in), contributing to a notably humid environment with levels hovering around 80%. Residents and visitors alike should prepare for a wet and cold December, making it a time for cozy indoor activities and festive celebrations.

December Temperature in Hyannis

In December, Hyannis experiences a noticeable dip in temperatures, with the minimum plunging to -12°C (11°F), while the average hovers around a brisk 4°C (40°F). As the month progresses, the maximum temperature reaches a moderate 15°C (60°F), signaling a chillier transition from the fall months. Compared to the milder November, December's cooler patterns emphasize the onset of winter, bridging the gap between the lingering autumnal warmth and the deep freeze of January. This contrast highlights the seasonal shift, encouraging residents and visitors to prepare for the cold while still enjoying the occasional warmer day.

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.
JanFebMarAprMayJunJulAugSepOctNovDec353638455363707266594839
Data source: Temperature data for Hyannis generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Hyannis

In December, Hyannis experiences 136 mm (5.4 in) of precipitation over approximately 12 days, signaling a shift towards the wetter winter months. This amount is slightly lower than October's peak of 175 mm (6.9 in) but remains relatively high compared to the earlier months of the year, indicating a steady pattern of moisture as the year closes. Notably, December's rainfall is on par with April's and slightly higher than November's, showcasing a consistent trend of significant winter precipitation that contributes to the region's seasonal transition. As the cold sets in, residents can expect a mix of rain and the potential for snow, especially as winter progresses.

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.
JanFebMarAprMayJunJulAugSepOctNovDec94123118137119918382118175102136
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, United States, the December humidity remains relatively high at 80%, mirroring the levels seen in both November and the cold winter months of January and February, which consistently hover around 84%. This trend suggests that as the year winds down, residents of Hyannis can expect moist air that carries over from the autumn season. Notably, after a slight decline to 75% in the warmer months of May through October, humidity begins to rise again as temperatures drop, indicating a seasonal pattern where colder months bring increased moisture. Overall, December's humidity reflects a return to the higher averages characteristic of New England winters, creating a chilly yet damp atmosphere as the year concludes.

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, allowing you to see how December's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%82%79%75%78%76%76%76%75%80%80%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Hyannis

In Hyannis, December brings a noticeable decline in the UV Index, dropping to 2, which falls into the low exposure category. This lower UV rating allows for a more forgiving burn time of 45 minutes, making it an ideal time for outdoor activities without the immediate concern of sunburn. This trend of diminishing UV levels is consistent as the year progresses; starting from a moderate index in January, the UV levels peak during the summer months before tapering down in the fall and early winter. Such fluctuations highlight the importance of staying informed about the UV Index, especially for those keen on enjoying the beauty of Hyannis. For more details, check out Hyannis UV Index.

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.
JanFebMarAprMayJunJulAugSepOctNovDec3468910998642
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.

December Sunshine in Hyannis

As December unfolds in Hyannis, United States, a gentle decline in sunshine hours marks the transition into winter. With 165 hours of sunlight, the month reflects a notable decrease from the sunshine peaks of summer, where July and June bask in over 300 hours each. Interestingly, December's light follows a trend of diminishing daylight that begins from the glorious bloom of May with 298 hours, gently tapering off throughout the fall. Despite this seasonal shift, the charm of Hyannis remains, as the crisp air and festive spirit provide a delightful contrast to the quieter days of sunlight. As the year wraps up, the community embraces the cozy ambiance, making the most of the beautiful, albeit fewer, hours of winter sunshine.

Monthly Sunshine Duration in Hyannis: December Highlighted

The December sunshine duration represents the total number of hours Hyannis experiences direct sunlight during the month of December, excluding cloudy or obstructed periods. This chart compares the sunshine duration of December with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec142h184h258h243h298h326h346h330h280h236h203h165h
Data source: Hyannis December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Hyannis During December

In December, the likelihood of sunny weather in Hyannis, United States, dips to 28%, making it one of the cloudier months of the year. This trend is consistent as we transition from the more optimistic 52% chance of sun in November, with October and September also showcasing relatively higher probabilities of sunshine at 44% and 49% respectively. As winter approaches, the chances of clear skies decrease more noticeably, with December wrapping up the year at one of its lowest points. This pattern hints that while the earlier months may offer glimpses of brightness, December is likely to be marked by overcast skies, encouraging cozy indoor activities rather than sunny outings.

Percentage of Sunny Days in December in Hyannis

The chart illustrates the percentage of sunny days in Hyannis throughout the year, with December highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Hyannis experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec36%28%57%43%41%38%37%35%49%44%52%28%
Data source: Hyannis December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Hyannis in December

In Hyannis, United States, the December daylight duration mirrors that of January, both offering about 9 hours of sunlight each day. As the year progresses, there's a notable increase in daylight, starting from 9 hours in January to a peak of 15 hours by June, reflecting the gradual shift towards longer days in the warmer months. Following this peak, daylight begins to wane, with July and August showcasing 14 and 13 hours respectively, before tapering off to 12 hours in September and 11 hours in October. The months of November and December then settle back to the shorter daylight hours, giving a cyclical feel to the changing seasons, as the sunlight diminishes alongside the temperature. This pattern underscores the rhythmic nature of seasonal shifts, marking both the chill of winter and the promises of brighter days ahead.

Average Daylight Hours in Hyannis for December

The chart illustrates the variation in daylight duration in Hyannis throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 31m10h 36m11h 58m13h 22m14h 33m15h 8m14h 49m13h 45m12h 25m11h 1m9h 48m9h 11m
Data source: Hyannis daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Hyannis

As December rolls into Hyannis, the wind picks up slightly, averaging 6.6 m/s (15 mph), a trend that mirrors the consistent breezes of the preceding months. After a gradual decline from the summer’s gentle 4.8 m/s (11 mph) in August to the more robust gusts seen at the start of winter, December's winds maintain a steady pace akin to those in October and November. This stability suggests that as the year closes, the winds turn slightly brisker, providing a crisp atmosphere that perfectly complements the scenic coastal charm of Cape Cod in winter. The relatively moderate wind speed also hints at a lingering warmth from the autumn months, inviting residents and visitors alike to enjoy beach walks and outdoor activities amidst the invigorating sea air.

Average December Wind Speed in Hyannis

The chart displays monthly wind speed patterns in Hyannis, with values for each month shown alongside December's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how December's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec7.17.27.06.55.96.25.24.85.96.66.76.6 m/s
Data source: Hyannis December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Hyannis Compares to Other Months

The weather in Hyannis changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Hyannis and find detailed weather information for every month.

December and January exhibit some notable differences in weather patterns. December tends to have slightly milder temperatures, with an average of 4°C (40°F) compared to January's average of 2°C (36°F). The minimum temperatures in January dip lower, reaching -14°C (6°F), while December's minimum is -12°C (11°F). Precipitation in December is also higher, at 136 mm (5.4 in) over 12 days, compared to January's 94 mm (3.7 in) across 10 days. Additionally, January experiences a slight increase in humidity, averaging 84% versus December's 80%. For more specific insights into January's climate, check out Hyannis weather in January.

December and February exhibit similar cold temperature ranges, with both months experiencing minimum lows of around -12°C (11°F) and -12°C (10°F), respectively. However, December tends to be slightly warmer on average, with temperatures reaching an average of 4°C (40°F) compared to February's average of 2°C (36°F). Precipitation levels are also comparable, with December receiving 136 mm (5.4 in) over 12 days, slightly higher than February's 123 mm (4.8 in) over the same number of days. Humidity levels are marginally higher in February at 84%, compared to December's 80%. For more information, check out Hyannis weather in February.

In December, temperatures range from a chilly minimum of -12°C (11°F) to a more moderate maximum of 15°C (60°F), with an average temperature hovering around 4°C (40°F). The month experiences considerable precipitation, totaling 136 mm (5.4 in) over about 12 days, and the humidity level is relatively high at 80%. In contrast, March sees slightly milder weather with temperatures varying from a minimum of -9°C (16°F) to a maximum of 13°C (56°F), averaging about 3°C (38°F). The precipitation levels decrease to 118 mm (4.7 in) across 10 days, while humidity rises marginally to 82%. For a detailed look at the climate during March, you can check Hyannis weather in March.

December and April display notably different weather patterns, reflecting the transition from winter to spring. December experiences colder temperatures, with minimums reaching as low as -12°C (11°F) and an average of 4°C (40°F), while April is milder, starting at a minimum of 1°C (33°F) and averaging 7°C (46°F). Both months receive similar amounts of precipitation—136 mm (5.4 in) in December and 137 mm (5.4 in) in April—though December has slightly fewer rainy days (12) compared to April's 13. Additionally, the humidity levels are comparable, with December at 80% and April at 79%. For those interested in more specific details about April weather, you can visit Hyannis weather in April.

In comparing the weather conditions of December and May, we see a stark contrast in temperatures and overall climate. December experiences much colder temperatures, with a minimum of -12°C (11°F) and an average peak of only 15°C (60°F), while May showcases a milder range, featuring a minimum of 5°C (41°F) and a comfortable maximum of 21°C (70°F). Precipitation is relatively similar in both months, with December receiving 136 mm (5.4 in) over 12 days and May slightly less at 119 mm (4.7 in) during the same number of days. Additionally, December's higher humidity level of 80% lends a chill to the air, compared to the more pleasant 75% humidity in May. For more detailed insights, you can check Hyannis weather in May.

December and June present stark contrasts in weather patterns. In December, temperatures can drop as low as -12°C (11°F), with an average of around 4°C (40°F) and highs reaching just 15°C (60°F). The month is also characterized by significant precipitation, totaling 136 mm (5.4 in) over approximately 12 days, accompanied by high humidity levels averaging 80%. In contrast, June enjoys milder temperatures with a minimum of 10°C (51°F), an average of 17°C (63°F), and maximums soaring to 24°C (76°F). Additionally, June receives less precipitation, around 91 mm (3.6 in) across 10 days, with humidity slightly lower at 78%. For more specific details, visit Hyannis weather in June.

December and July present strikingly different weather patterns. In December, temperatures can plunge to a minimum of -12°C (11°F), with an average of 4°C (40°F) and a maximum reaching 15°C (60°F). The month sees significant precipitation with 136 mm (5.4 in) over approximately 12 days, contributing to a humidity level of 80%. In contrast, July offers a much warmer climate, with minimum temperatures of 16°C (61°F) and averages around 21°C (71°F), peaking at 29°C (84°F). The precipitation in July is lighter at 83 mm (3.3 in) over about 9 days, and the humidity is slightly lower at 76%. For a more detailed view of the summer weather, check out Hyannis weather in July.

When comparing the weather in December and August, it's evident that they offer vastly different climates. December experiences colder temperatures, with a minimum of -12°C (11°F) and an average of around 4°C (40°F), while August enjoys milder conditions, with temperatures ranging from a minimum of 16°C (61°F) to an average of 22°C (72°F). Precipitation is more frequent in December, occurring on 12 days and totaling 136 mm (5.4 in), compared to August's 8 days of rain and 82 mm (3.2 in). Additionally, December features higher humidity levels at 80%, while August maintains a slightly lower humidity of 76%. For more details on August weather specifics, you can check Hyannis weather in August.

In December, the weather is significantly colder, with temperatures ranging from a chilly min of -12°C (11°F) to a max of 15°C (60°F) and an average of 4°C (40°F). In contrast, September enjoys milder conditions, with temperatures typically between 13°C (56°F) and 25°C (78°F), averaging around 19°C (67°F). Additionally, December experiences higher precipitation levels of 136 mm (5.4 in) over 12 days, while September sees slightly less at 118 mm (4.7 in) over 10 days. Humidity levels are also higher in December at 80%, compared to 75% in September. For more details on September weather, you can visit Hyannis weather in September.

When comparing the weather in December to October, it's clear that December is significantly colder, with minimum temperatures plunging to -12°C (11°F) compared to October's milder minimum of 4°C (39°F). The average temperature in December is around 4°C (40°F), whereas October enjoys a more comfortable average of 15°C (59°F). Precipitation levels are also noteworthy: December sees about 136 mm (5.4 in) of rainfall over 12 days, while October has slightly higher precipitation at 175 mm (6.9 in), with the same number of rainy days. Humidity levels in December average around 80%, higher than October's 75%, contributing to a chillier and damp atmosphere. For more details on October weather, you can visit Hyannis weather in October.

In comparing the weather between November and December, it's clear that December tends to be colder, with temperatures ranging from a minimum of -12°C (11°F) to a maximum of 15°C (60°F), whereas November sees milder temperatures from a low of -6°C (21°F) to a high of 19°C (66°F). Additionally, December experiences more precipitation, averaging 136 mm (5.4 in) over 12 days, compared to November's 102 mm (4.0 in) over 10 days. Despite the increased rainfall in December, both months maintain a consistent humidity level of 80%. For more details on November weather patterns, you can visit Hyannis weather in November.

Compare Hyannis's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in Hyannis

As December settles into Hyannis, the weather takes a noticeable turn, offering a blend of chilly temperatures and increased precipitation that sets it apart from the milder months of the year. This month typically brings cooler average temperatures, with maximums rarely reaching above 15°C, contrasting sharply with the warmth of summer. Additionally, December is marked by higher humidity levels and frequent rainy days, contributing to a dampness that softens the coastal landscape. The overall atmosphere encapsulates the transition into winter, making it a unique and reflective time to experience the charm of Hyannis. For more insights on climate patterns, visit Hyannis Climate.