December weather forecast
South Lyme, CT

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Weather in December

The first month of the winter, December, is also an icy month in South Lyme, Connecticut, with temperature in the range of an average low of 32.4°F (0.2°C) and an average high of 41.9°F (5.5°C).

Temperature

In the transition to December, South Lyme observes a drop in the average high-temperature, moving from a fresh 50.9°F (10.5°C) in November to a wintry 41.9°F (5.5°C). South Lyme, in December, witnesses an average low-temperature of 32.4°F (0.2°C).

Humidity

In South Lyme, the average relative humidity in December is 75%.

Rainfall

December is the month with the most rainfall. Rain falls for 9.5 days and accumulates 0.94" (24mm) of precipitation.

Snowfall

Months with snowfall are January through March, November and December. In December, in South Lyme, it is snowing for 3.2 days. Throughout December, 0.28" (7mm) of snow is accumulated. In South Lyme, Connecticut, during the entire year, snow falls for 18.4 days and aggregates up to 1.69" (43mm) of snow.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year in South Lyme, Connecticut.
On the first day of December in South Lyme, sunrise is at 6:56 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 4:29 pm EST.

Sunshine

February and December, with an average of 4.8h of sunshine, are months with the least 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 of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 2 in December translates into the following recommendations:
Prolonged exposure to sunlight rarely troubles the majority, but constant protection is vital for babies, children, and fair-skinned people. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
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Frequently asked questions

Is December cold in South Lyme?

The average high-temperature, in December, in South Lyme, is 41.9°F (5.5°C), while the average low-temperature is 32.4°F (0.2°C).

What is the average humidity in December in South Lyme?

The average relative humidity in December in South Lyme is 75%.

What is the rainiest month in South Lyme?

December is the month with the most rainfall in South Lyme. Rain falls for 9.5 days and accumulates 0.94" (24mm) of precipitation.

How much does it rain in South Lyme in December?

In South Lyme, in December, it is raining for 9.5 days, with typically 0.94" (24mm) of accumulated precipitation.

How many days does it snow in December in South Lyme?

In South Lyme, during December, snow falls for 3.2 days and regularly aggregates up to 0.28" (7mm) of snow.

What is the month with the shortest days in South Lyme?

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

How many hours of daylight does South Lyme have in December?

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

What time are sunrise and sunset in December in South Lyme?

In December, on the first day of the month, sunrise is at 6:56 am and sunset at 4:20 pm. On the last day of the month, in South Lyme, sunrise is at 7:14 am and sunset at 4:29 pm EST.

What are the months with the least sunshine in South Lyme?

The months with the least sunshine are February and December, with an average of 4.8h of sunshine.

How long on average sun shines in December in South Lyme?

In South Lyme, Connecticut, the average sunshine duration in December is 4.8h.

When is the lowest UV index in South Lyme?

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 in South Lyme?

In December, the average daily maximum UV index in South Lyme, Connecticut, is 2. A UV Index reading of 2, and below, represents a minimal hazard to health 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
South Lyme, CT

Average temperature in December - South Lyme, CT
  • Average high temperature in December: 41.9°F

The warmest month (with the highest average high temperature) is July (79.5°F).
The month with the lowest average high temperature is January (35.4°F).

  • Average low temperature in December: 32.4°F

The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).

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Average pressure in December
South Lyme, CT

Average pressure in December - South Lyme, 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).

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Average wind speed in December
South Lyme, CT

Average wind speed in December - South Lyme, CT
  • Average wind speed in December: 10.7mph

The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).

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Average humidity in December
South Lyme, CT

Average humidity in December - South Lyme, CT
  • Average humidity in December: 75%

The months with the highest relative humidity are June and July (79%).
The month with the lowest relative humidity is April (73%).

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Average rainfall in December
South Lyme, CT

Average rainfall in December - South Lyme, CT
  • Average rainfall in December: 0.94"

The wettest month (with the highest rainfall) is December (0.94").
The driest month (with the least rainfall) is September (0.35").

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Average rainfall days in December
South Lyme, CT

Average rainfall days in December - South Lyme, CT
  • Average rainfall days in December: 9.5 days

The month with the highest number of rainy days is July (11.5 days).
The months with the least rainy days are February and November (6.6 days).

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Average snowfall in December
South Lyme, CT

Average snowfall in December - South Lyme, CT
  • Average snowfall in December: 0.28"

The month with the highest snowfall is March (0.63").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
South Lyme, CT

Average snowfall days in December - South Lyme, CT
  • Average snowfall days in December: 3.2 days

The month with the highest number of snowfall days is January (5.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
South Lyme, CT

Average daylight in December / Average sunshine in December - South Lyme, 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 months with the most sunshine are July and August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).

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Average sunshine days in December
South Lyme, CT

Average sunshine days in December - South Lyme, CT
  • Average sunshine days in December: 19.7 days

The month with the most sunshine days is November (21.1 days).
The month with the least sunshine days is July (15.8 days).

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Average UV index in December
South Lyme, CT

Average UV index in December - South Lyme, 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).

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Average cloud cover in December
South Lyme, CT

Average cloud cover in December - South Lyme, 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 28).

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Average visibility in December
South Lyme, CT

Average visibility in December - South Lyme, 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).

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South Lyme, Connecticut, USA

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