Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average sea temperature in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
With the arrival of December, Rockland experiences a modest decline in average high-temperatures, transitioning from a chilly 45.5°F (7.5°C) in November to a wintry 37°F (2.8°C). December nights anticipate an average temperature of 28.4°F (-2°C), a modest decline from the daytime.Humidity
The average relative humidity in December is 77%.Rainfall
The month with the most rainfall is December, when the rain falls for 11.3 days and typically aggregates up to 3.35" (85mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. In December, it is snowing for 6.5 days. Throughout December, 1.81" (46mm) of snow is accumulated. Throughout the year, there are 33.1 snowfall days, and 12.36" (314mm) of snow is accumulated.Ocean temperature
In Rockland, the average seawater temperature in December is 45.1°F (7.3°C).Note: Engaging in a swim in 45.1°F (7.3°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 8h and 54min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 6:52 am and sunset at 3:59 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 4:08 pm EST.
Sunshine
December has the least sunshine of the year, with an average of 4.5h of sunshine.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from unprotected exposure to Sun's UV rays for the average person.Note: In December, a regular UV index of 2 translates into these guidelines:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Be mindful! The reflection from snow can increase the Sun's UV radiation nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
What is the rainiest month?
How much does it rain in December?
How much does it snow in Rockland in December?
What is the ocean temperature in December?
What is the month with the shortest days?
How many hours of daylight does Rockland have in December?
When is the sunrise / sunset in December?
What is the month with the least sunshine?
How many hours of sunshine does Rockland have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Rockland, ME
- Average high temperature in December: 37°F
The warmest month (with the highest average high temperature) is August (68.7°F).
The month with the lowest average high temperature is January (31.8°F).
- Average low temperature in December: 28.4°F
The month with the highest average low temperature is August (60.6°F).
The coldest month (with the lowest average low temperature) is January (22.1°F).
Average pressure in December
Rockland, ME
- Average pressure in December: 30"Hg
The month with the highest atmospheric pressure is September (30.04"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Rockland, ME
- Average wind speed in December: 14.4mph
The windiest month (with the highest average wind speed) is January (14.9mph).
The calmest months (with the lowest average wind speed) are July and August (8.2mph).
Average humidity in December
Rockland, ME
- Average humidity in December: 77%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is November (75%).
Average rainfall in December
Rockland, ME
- Average rainfall in December: 3.35"
The wettest month (with the highest rainfall) is December (3.35").
The driest month (with the least rainfall) is September (1.81").
Average rainfall days in December
Rockland, ME
- Average rainfall days in December: 11.3 days
The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is January (7.9 days).
Average snowfall in December
Rockland, ME
- Average snowfall in December: 1.81"
The month with the highest snowfall is January (2.83").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Rockland, ME
- Average snowfall days in December: 6.5 days
The month with the highest number of snowfall days is January (8.5 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average sea temperature in December
Rockland, ME
- Average sea temperature in December: 45°F
The best month for swimming (with the highest average sea temperature) is August (60.4°F).
The coldest month (with the lowest average sea temperature) is March (37.8°F).
Average daylight in December /
Average sunshine in December
Rockland, ME
- Average daylight in December: 8h and 5min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in December: 4h and 3min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 4h and 30min).
Average sunshine days in December
Rockland, ME
- Average sunshine days in December: 12.3 days
The month with the most sunshine days is September (18 days).
The month with the least sunshine days is April (11.5 days).
Average UV index in December
Rockland, ME
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in December
Rockland, ME
- Average cloud cover in December: 51
The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in December
Rockland, ME
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Rockland, Maine, USA
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