Weather in December
Ocean temperature
In December, the average ocean temperature in Mystic Island, New Jersey, is 48.6°F (9.2°C).Note: Diving into 48.6°F (9.2°C) when it's under 50°F (10°C) can cause immediate cold shock symptoms, marked by hyperventilation.
Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of December, sunrise is at 6:59 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:43 pm EST.
Updated: Aug 29, 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 Mystic Island, the average seawater temperature in December is 48.6°F (9.2°C). Swimming in 48.6°F (9.2°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.
What is the month with the shortest days?
The month with the shortest days is December, with an average of 9h and 24min of daylight.
What is the average length of the day in December?
The average day length in December is 9h and 26min.
When is the sunrise / sunset in December?
In December, on the first day of the month, sunrise is at 6:59 am and sunset at 4:34 pm. On the last day of the month, in Mystic Island, sunrise is at 7:17 am and sunset at 4:43 pm EST.
Average sea temperature in December
Mystic Island, NJ
- Average sea temperature in December: 48.5°F
The best month for swimming (with the highest average sea temperature) is August (75.8°F).
The coldest month (with the lowest average sea temperature) is February (40.8°F).
Average daylight in December
Mystic Island, NJ
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
Mystic Island, New Jersey, USA
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