December weather forecast
Haddam, CT

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Weather in December

The first month of the winter, December, is also an icy month in Haddam, Connecticut, with an average temperature fluctuating between 40.6°F (4.8°C) and 30°F (-1.1°C).

Temperature

The shift from November to December corresponds with a decrease in the average high-temperature, down to an icy 40.6°F (4.8°C) from a fresh 50°F (10°C). During December, the temperature in Haddam is averaged to a low of 30°F (-1.1°C) at night.

Humidity

The average relative humidity in December is 76%.

Rainfall

In December, the rain falls for 8.6 days. Throughout December, 1.14" (29mm) of precipitation is accumulated. Throughout the year, there are 109.9 rainfall days, and 11.14" (283mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, November and December. In Haddam, in December, during 3.7 snowfall days, 0.55" (14mm) of snow is typically accumulated. Throughout the year, there are 19.9 snowfall days, and 3.7" (94mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 12min of daylight.
On the first day of the month, sunrise is at 6:57 am and sunset at 4:21 pm. On the last day of December, sunrise is at 7:16 am and sunset at 4:30 pm EST.

Sunshine

In December, the average sunshine is 4.6h.

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 of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 2 in December translates into these instructions:
Despite the majority tolerating prolonged sun exposure, those with sensitive skin, infants, and children demand continual protection. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it cold during December?

In Haddam, in December, the average high-temperature is 40.6°F (4.8°C), and the average low-temperature is 30°F (-1.1°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines relative humidity and air temperature, in July is evaluated at 89.6°F (32°C).

What is the average humidity in December?

The average relative humidity in December in Haddam is 76%.

How much does it rain in December?

In December, the rain falls for 8.6 days. Throughout December, 1.14" (29mm) of precipitation is accumulated.

How many days does it snow in December?

In December, it is snowing for 3.7 days. Throughout December, 0.55" (14mm) of snow is accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 12min of daylight.

How many hours of daylight does Haddam have in December?

In Haddam, the average day length in December is 9h and 14min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 6:57 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 4:30 pm EST.

How many hours of sunshine does Haddam have in December?

In Haddam, the average sunshine duration in December is 4.6h.

What are the months with 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 intensity in December?

In Haddam, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to 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
Haddam, CT

Average temperature in December - Haddam, CT
  • Average high temperature in December: 40.6°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (34.7°F).

  • Average low temperature in December: 30°F

The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (22.8°F).

Average pressure in December
Haddam, CT

Average pressure in December - Haddam, CT
  • Average pressure in December: 30.05"Hg

The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Haddam, CT

Average wind speed in December - Haddam, CT
  • Average wind speed in December: 8.4mph

The windiest months (with the highest average wind speed) are January and March (8.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).

Average humidity in December
Haddam, CT

Average humidity in December - Haddam, CT
  • Average humidity in December: 76%

The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (72%).

Average rainfall in December
Haddam, CT

Average rainfall in December - Haddam, CT
  • Average rainfall in December: 1.14"

The wettest month (with the highest rainfall) is July (1.18").
The driest month (with the least rainfall) is September (0.39").

Average rainfall days in December
Haddam, CT

Average rainfall days in December - Haddam, CT
  • Average rainfall days in December: 8.6 days

The month with the highest number of rainy days is July (12.7 days).
The month with the least rainy days is January (5.9 days).

Average snowfall in December
Haddam, CT

Average snowfall in December - Haddam, CT
  • Average snowfall in December: 0.55"

The month with the highest snowfall is March (1.14").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Haddam, CT

Average snowfall days in December - Haddam, CT
  • Average snowfall days in December: 3.7 days

The month with the highest number of snowfall days is February (5.2 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Haddam, CT

Average daylight in December / Average sunshine in December - Haddam, CT
  • Average daylight in December: 9h and 1min

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 12min).

  • Average sunshine in December: 4h and 4min

The months with the most sunshine are July and August (Average sunshine: 10h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in December
Haddam, CT

Average sunshine days in December - Haddam, CT
  • Average sunshine days in December: 19.2 days

The month with the most sunshine days is November (20.9 days).
The month with the least sunshine days is July (16.3 days).

Average UV index in December
Haddam, CT

Average UV index in December - Haddam, 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
Haddam, CT

Average cloud cover in December - Haddam, CT
  • Average cloud cover in December: 50

The months with the most cloud cover are February and March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 35).

Average visibility in December
Haddam, CT

Average visibility in December - Haddam, CT
  • Average visibility in December: 6mi

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

Haddam, Connecticut, USA

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