December weather forecast
New Haven, CT

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The greeny New Haven Green in Connecticut, with the rest of the city and a far away dramatic landscape
The greeny New Haven Green in Connecticut, with the rest of the city and a far away dramatic landscape

Weather in December

December welcomes the onset of winter in New Haven, Connecticut, USA, demonstrating temperatures as low as 32.5°F (0.3°C). Evenings turn cold earlier, marking the arrival of long winter nights. Despite its chilly attributes, locals enjoy the festivity brought in by the Christmas season. The first snowfall makes its entry, preparing New Haven for the beautiful, icy landscapes of the following months. By December, the city is transformed into a winter wonderland, capping the year with a snowy marvel.

Temperature

Welcoming December, New Haven observes a shift in the average high-temperature, falling from November's fresh 50.7°F (10.4°C) to a cold 41.7°F (5.4°C). In New Haven, the expected average low-temperature for December is 32.5°F (0.3°C).

Humidity

In December, the average relative humidity in New Haven is 75%.

Rainfall

The month with the most rainfall in New Haven is December, when the rain falls for 12.5 days and typically aggregates up to 3.86" (98mm) of precipitation.

Snowfall

Months with snowfall in New Haven are January through April, November and December. In December, it is snowing for 3.5 days. Throughout December, 1.34" (34mm) of snow is accumulated. Throughout the year, in New Haven, there are 23.1 snowfall days, and 9.21" (234mm) of snow is accumulated.

Ocean temperature

In New Haven, the average seawater temperature in December is 48.7°F (9.3°C).
Note: Engaging in a swim in 48.7°F (9.3°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 9h and 18min of daylight, December has the shortest days of the year.
On the first day of December in New Haven, sunrise is at 6:58 am and sunset at 4:23 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:32 pm EST.

Sunshine

In December, the average sunshine is 4.8h.

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 reading of 2, and below, represents a low health risk from exposure to the Sun's UV rays for the ordinary person.
Note: The UV index of 2 during December leads to these advisories:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties of snow.

Frequently asked questions

How cold does it get in New Haven in December?

During December, New Haven experiences an average high-temperature of 41.7°F (5.4°C) and a low-temperature of 32.5°F (0.3°C).

What is the average humidity in December in New Haven?

The average relative humidity in December is 75%.

What is the rainiest month in New Haven?

The month with the most rainfall in New Haven, Connecticut, is December, when the rain falls for 12.5 days and typically aggregates up to 3.86" (98mm) of precipitation.

How much does it rain in New Haven in December?

In New Haven, during December, the rain falls for 12.5 days and regularly aggregates up to 3.86" (98mm) of precipitation.

How much does it snow in New Haven in December?

In New Haven, in December, during 3.5 snowfall days, 1.34" (34mm) of snow is typically accumulated.

How cold is the water in December in New Haven?

In December, the average ocean temperature in New Haven, Connecticut, is 48.7°F (9.3°C). Swimming in 48.7°F (9.3°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 in New Haven?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

How many hours of daylight does New Haven have in December?

In New Haven, Connecticut, the average day length in December is 9h and 15min.

When is the sunrise / sunset in December in New Haven?

On the first day of December in New Haven, sunrise is at 6:58 am and sunset at 4:23 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:32 pm EST.

How many hours of sunshine does New Haven have in December?

The average sunshine duration in December is 4.8h.

What is the month with the lowest UV index in New Haven?

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

How high is the UV index in December in New Haven?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a low health threat from exposure to the Sun's UV radiation.
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
New Haven, CT

Average temperature in December - New Haven, CT
  • Average high temperature in December: 41.7°F

The warmest month (with the highest average high temperature) is July (80.4°F).
The month with the lowest average high temperature is January (35.1°F).

  • Average low temperature in December: 32.5°F

The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (25.5°F).

Average pressure in December
New Haven, CT

Average pressure in December - New Haven, CT
  • Average pressure in December: 30.06"Hg

The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
New Haven, CT

Average wind speed in December - New Haven, CT
  • Average wind speed in December: 10.2mph

The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).

Average humidity in December
New Haven, CT

Average humidity in December - New Haven, CT
  • Average humidity in December: 75%

The months with the highest relative humidity are February, May and June (76%).
The months with the lowest relative humidity are April and November (72%).

Average rainfall in December
New Haven, CT

Average rainfall in December - New Haven, CT
  • Average rainfall in December: 3.86"

The wettest month (with the highest rainfall) is December (3.86").
The driest month (with the least rainfall) is September (2.24").

Average rainfall days in December
New Haven, CT

Average rainfall days in December - New Haven, CT
  • Average rainfall days in December: 12.5 days

The month with the highest number of rainy days is July (18 days).
The month with the least rainy days is January (9.4 days).

Average snowfall in December
New Haven, CT

Average snowfall in December - New Haven, CT
  • Average snowfall in December: 1.34"

The month with the highest snowfall is March (2.8").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
New Haven, CT

Average snowfall days in December - New Haven, CT
  • Average snowfall days in December: 3.5 days

The month with the highest number of snowfall days is February (7.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average sea temperature in December
New Haven, CT

Average sea temperature in December - New Haven, CT
  • Average sea temperature in December: 48.7°F

The best month for swimming (with the highest average sea temperature) is August (73°F).
The coldest month (with the lowest average sea temperature) is February (38.5°F).

Average daylight in December /
Average sunshine in December
New Haven, CT

Average daylight in December / Average sunshine in December - New Haven, CT
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).

Average sunshine days in December
New Haven, CT

Average sunshine days in December - New Haven, CT
  • Average sunshine days in December: 15.4 days

The month with the most sunshine days is November (17.3 days).
The month with the least sunshine days is August (11.3 days).

Average UV index in December
New Haven, CT

Average UV index in December - New Haven, CT
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in December
New Haven, CT

Average cloud cover in December - New Haven, CT
  • Average cloud cover in December: 48

The months with the most cloud cover are February and December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in December
New Haven, CT

Average visibility in December - New Haven, CT
  • 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).

New Haven, Connecticut, USA

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