Weather in December
December marks the return of winter conditions at Cape Cod National Seashore. With a significant plunge in sea temperature to 46.1°F (7.8°C), the cold weather asserts its dominance. Daylight diminishes, averaging 9.2 hours per day, creating shorter days and longer nights. Tumbled between November's cold incline and January's bone-chilling cold, December exhibits a robust transition to the frigid winter months.
Note: Engaging in a swim in 46°F (7.8°C) can threaten life. Brief exposure to 55.4°F (13°C) waters is uneasy, and submersion below 50°F (10°C) can lead to cold shock and disrupted breathing patterns, varying by individual.
On the first day of December, sunrise is at 6:48 am and sunset at 4:09 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 4:18 pm EST.
Ocean temperature
In Cape Cod National Seashore, the average seawater temperature in December is 46°F (7.8°C).Note: Engaging in a swim in 46°F (7.8°C) can threaten life. Brief exposure to 55.4°F (13°C) waters is uneasy, and submersion below 50°F (10°C) can lead to cold shock and disrupted breathing patterns, varying by individual.
Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 6:48 am and sunset at 4:09 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 4:18 pm EST.
Updated: Jun 4, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is the water in December?
In Cape Cod National Seashore, Massachusetts, the average seawater temperature in December is 46°F (7.8°C). Swimming in 46°F (7.8°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.
What is the month with the shortest days?
With an average of 9h and 12min of daylight, December has the shortest days of the year.
How many hours of daylight does Cape Cod National Seashore have in December?
In December, the average day length is 9h and 11min.
When is the sunrise / sunset in December?
In December, on the first day of the month, sunrise is at 6:48 am and sunset at 4:09 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 4:18 pm EST.
Average sea temperature in December
Cape Cod National Seashore, MA
- Average sea temperature in December: 46.1°F
The best month for swimming (with the highest average sea temperature) is August (67.5°F).
The coldest month (with the lowest average sea temperature) is March (39°F).
Average daylight in December
Cape Cod National Seashore, MA
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
Cape Cod National Seashore, Massachusetts, USA
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