December weather forecast
Castine, ME

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Weather in December

December, the first month of the winter in Castine, is also an icy month, with an average temperature fluctuating between 34.2°F (1.2°C) and 24.1°F (-4.4°C).

Temperature

Castine in December experiences a subtle temperature decline, with average high-temperatures reducing from a frosty 44.1°F (6.7°C) in November to a wintry 34.2°F (1.2°C). Castine experiences an average low-temperature reading of 24.1°F (-4.4°C) throughout December.

Humidity

In Castine, the average relative humidity in December is 79%.

Rainfall

December is the month with the most rainfall. Rain falls for 10.1 days and accumulates 2.72" (69mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Castine, during December, snow falls for 8.9 days and regularly aggregates up to 2.28" (58mm) of snow. Throughout the year, there are 44.3 snowfall days, and 16.81" (427mm) of snow is accumulated.

Ocean temperature

In Castine, the average seawater temperature in December is 45.5°F (7.5°C).
Note: Dipping into 45.5°F (7.5°C) below 50°F (10°C) needs protective wear, or you'd face cold shock and breathing issues swiftly. Meanwhile, a slight swim around 55.4°F (13°C) feels cold to the bone.

Daylight

December has the shortest days of the year, with an average of 8h and 54min of daylight.
On the first day of December, sunrise is at 6:51 am and sunset at 3:57 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 4:05 pm EST.

Sunshine

In December, the average sunshine in Castine is 4.4h.

UV index

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 2 during December, leads to the following recommendations:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.

Frequently asked questions

How cold is December?

The high-temperature, in December, in Castine, records 34.2°F (1.2°C), while the low-temperature is 24.1°F (-4.4°C).

What is the average humidity in December?

In December, the average relative humidity is 79%.

What is the rainiest month?

The month with the most rainfall is December, when the rain falls for 10.1 days and typically aggregates up to 2.72" (69mm) of precipitation.

How many days does it rain in December?

In Castine, during December, the rain falls for 10.1 days and regularly aggregates up to 2.72" (69mm) of precipitation.

How many days does it snow in December?

In Castine, Maine, during December, snow falls for 8.9 days and regularly aggregates up to 2.28" (58mm) of snow.

How cold is the water in December?

In Castine, the average seawater temperature in December is 45.5°F (7.5°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days?

With an average of 8h and 54min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In Castine, the average day length in December is 8h and 55min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 6:51 am and sunset at 3:57 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 4:05 pm EST.

How long on average sun shines in December?

In Castine, the average sunshine duration in December is 4.4h.

When is the lowest UV index?

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2.

What is the UV index reading in December?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Castine, ME

Average temperature in December - Castine, ME
  • Average high temperature in December: 34.2°F

The warmest months (with the highest average high temperature) are July and August (73.9°F).
The month with the lowest average high temperature is January (28.4°F).

  • Average low temperature in December: 24.1°F

The month with the highest average low temperature is July (57.7°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).

Average pressure in December
Castine, ME

Average pressure in December - Castine, 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
Castine, ME

Average wind speed in December - Castine, ME
  • Average wind speed in December: 9.6mph

The windiest month (with the highest average wind speed) is March (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

Average humidity in December
Castine, ME

Average humidity in December - Castine, ME
  • Average humidity in December: 79%

The months with the highest relative humidity are February and July (83%).
The month with the lowest relative humidity is November (77%).

Average rainfall in December
Castine, ME

Average rainfall in December - Castine, ME
  • Average rainfall in December: 2.72"

The wettest month (with the highest rainfall) is December (2.72").
The driest months (with the least rainfall) are July and September (1.46").

Average rainfall days in December
Castine, ME

Average rainfall days in December - Castine, ME
  • Average rainfall days in December: 10.1 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (7.1 days).

Average snowfall in December
Castine, ME

Average snowfall in December - Castine, ME
  • Average snowfall in December: 2.28"

The month with the highest snowfall is January (4.57").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Castine, ME

Average snowfall days in December - Castine, ME
  • Average snowfall days in December: 8.9 days

The month with the highest number of snowfall days is January (10.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average sea temperature in December
Castine, ME

Average sea temperature in December - Castine, ME
  • Average sea temperature in December: 45.6°F

The best month for swimming (with the highest average sea temperature) is August (58.6°F).
The coldest month (with the lowest average sea temperature) is March (38.2°F).

Average daylight in December /
Average sunshine in December
Castine, ME

Average daylight in December / Average sunshine in December - Castine, ME
  • Average daylight in December: 8h and 5min

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in December: 4h and 2min

The month with the most sunshine is August (Average sunshine: 9h and 54min).
The month with the least sunshine is February (Average sunshine: 4h and 18min).

Average sunshine days in December
Castine, ME

Average sunshine days in December - Castine, ME
  • Average sunshine days in December: 14.5 days

The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is April (11.7 days).

Average UV index in December
Castine, ME

Average UV index in December - Castine, 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
Castine, ME

Average cloud cover in December - Castine, ME
  • Average cloud cover in December: 52

The month with the most cloud cover is March (Cloud cover 55).
The months with the least cloud cover are August and September (Cloud cover 37).

Average visibility in December
Castine, ME

Average visibility in December - Castine, ME
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, October, November and December (6mi).
The months with the lowest visibility are May, June, July, August and September (5mi).

Castine, Maine, USA

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