December weather forecast
Belfast, ME

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Weather in December

Winter makes its full-fledged entrance in Belfast during December. The weather becomes harsher, with cold temperatures and an increased amount of snowfall when compared to November. The month reaches its highest level of snowfall within the year - a significant 2.28" (58mm). The city morphs into a winter wonderland, with layers of snow covering streets, rooftops, and trees. Despite the cold, December’s festive spirit makes the weather conditions seem a little less harsh, offering a beautiful backdrop for ringing in the holiday season.

Temperature

December in Belfast brings a minor decrease, with the average high-temperature reducing from a frosty 44.1°F (6.7°C) in November to a cold 34.2°F (1.2°C). Belfast anticipates an average minimum temperature of 24.1°F (-4.4°C) in the month of December.

Humidity

In Belfast, 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

January through May, October through December are months with snowfall. In Belfast, during December, snow falls for 8.9 days and regularly aggregates up to 2.28" (58mm) of snow. In Belfast, during the entire year, snow falls for 44.3 days and aggregates up to 16.81" (427mm) of snow.

Ocean temperature

In Belfast, the average seawater temperature in December is 45.1°F (7.3°C).
Note: Danger awaits those who swim in 45.1°F (7.3°C) without protection. Falling below 50°F (10°C) means intense cold shock and hyperventilation.

Daylight

The month with the shortest days is December, with an average of 8h and 54min of daylight.
On the first day of the month, sunrise is at 6:52 am and sunset at 3:57 pm. On the last day of December, sunrise is at 7:12 am and sunset at 4:06 pm EST.

Sunshine

The average sunshine in December is 4.4h.

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 value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, a daily maximum UV index of 2 leads to the following instructions:
Most individuals face no significant issues with extended sun exposure, but it is always essential to protect children, babies, and those with sensitive skin. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.

Frequently asked questions

How cold is it in December?

An average high-temperature, in December, in Belfast, is 34.2°F (1.2°C) and the average low-temperature is 24.1°F (-4.4°C).

What is the average humidity in December?

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

What is the wettest 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 Belfast, in December, it is raining for 10.1 days, with typically 2.72" (69mm) of accumulated precipitation.

How much does it snow in December?

In December, it is snowing for 8.9 days. Throughout December, 2.28" (58mm) of snow is accumulated.

What is the water temperature in December?

In Belfast, in December, the average water temperature is 45.1°F (7.3°C). Swimming in 45.1°F (7.3°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?

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

What is the average length of the day in December?

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

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 6:52 am and sunset at 3:57 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 4:06 pm EST.

How long on average sun shines in December?

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

What is the month with the lowest UV index?

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

What is the UV index intensity in December?

The average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a low health threat from unsafe 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
Belfast, ME

Average temperature in December - Belfast, 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
Belfast, ME

Average pressure in December - Belfast, 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
Belfast, ME

Average wind speed in December - Belfast, 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
Belfast, ME

Average humidity in December - Belfast, 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
Belfast, ME

Average rainfall in December - Belfast, 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
Belfast, ME

Average rainfall days in December - Belfast, 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
Belfast, ME

Average snowfall in December - Belfast, 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
Belfast, ME

Average snowfall days in December - Belfast, 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
Belfast, ME

Average sea temperature in December - Belfast, 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
Belfast, ME

Average daylight in December / Average sunshine in December - Belfast, 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
Belfast, ME

Average sunshine days in December - Belfast, 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
Belfast, ME

Average UV index in December - Belfast, 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
Belfast, ME

Average cloud cover in December - Belfast, 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
Belfast, ME

Average visibility in December - Belfast, 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).

Belfast, Maine, USA

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