December weather forecast
Winthrop, MA

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Weather in December

The first month of the winter, December, is still a cold month in Winthrop, Massachusetts, with an average temperature ranging between min 29.7°F (-1.3°C) and max 39.9°F (4.4°C).

Temperature

Winthrop's progression into December involves a drop in the average high-temperature, receding from a frosty 49.5°F (9.7°C) in November to an icy 39.9°F (4.4°C). Winthrop temperatures generally rest at a low of 29.7°F (-1.3°C) during the December nights.

Humidity

In Winthrop, the average relative humidity in December is 76%.

Rainfall

The months with the most rainfall are March, April and December, with an average 2.91" (74mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Winthrop, during December, snow falls for 5.2 days and regularly aggregates up to 2.83" (72mm) of snow. Throughout the year, there are 29.8 snowfall days, and 15.75" (400mm) of snow is accumulated.

Ocean temperature

In Winthrop, the average seawater temperature in December is 46.2°F (7.9°C).
Note: Dipping into 46.2°F (7.9°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

With an average of 9h and 6min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 6:54 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:21 pm EST.

Sunshine

The average sunshine in December is 4.7h.

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 reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: A daily high UV index of 2 in December leads to these guidelines:
Unlike children, who always need sun protection, most individuals can remain in the sun for up to an hour without getting burnt. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.

Frequently asked questions

How cold is it in December?

An average high-temperature, in December, in Winthrop, is 39.9°F (4.4°C) and the average low-temperature is 29.7°F (-1.3°C). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in July is calculated to be 86°F (30°C).

What is the average humidity in December?

In Winthrop, the average relative humidity in December is 76%.

What is the wettest month?

The months with the most rainfall in Winthrop are March, April and December, with an average 2.91" (74mm) of precipitation.

How many days does it rain in December?

In Winthrop, in December, it is raining for 10.1 days, with typically 2.91" (74mm) of accumulated precipitation.

How much does it snow in December?

In Winthrop, in December, during 5.2 snowfall days, 2.83" (72mm) of snow is typically accumulated.

What is the water temperature in December?

In Winthrop, in December, the average water temperature is 46.2°F (7.9°C). Swimming in 46.2°F (7.9°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?

With an average of 9h and 6min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

The average day length in December is 9h and 8min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 6:54 am and sunset at 4:12 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 4:21 pm EST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.7h.

When is the lowest UV index?

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

What is the UV index intensity in December?

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability 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
Winthrop, MA

Average temperature in December - Winthrop, MA
  • Average high temperature in December: 39.9°F

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (34.2°F).

  • Average low temperature in December: 29.7°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).

Average pressure in December
Winthrop, MA

Average pressure in December - Winthrop, MA
  • Average pressure in December: 30.03"Hg

The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
Winthrop, MA

Average wind speed in December - Winthrop, MA
  • Average wind speed in December: 9.4mph

The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).

Average humidity in December
Winthrop, MA

Average humidity in December - Winthrop, MA
  • Average humidity in December: 76%

The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is April (69%).

Average rainfall in December
Winthrop, MA

Average rainfall in December - Winthrop, MA
  • Average rainfall in December: 2.91"

The wettest months (with the highest rainfall) are March, April and December (2.91").
The driest month (with the least rainfall) is September (1.26").

Average rainfall days in December
Winthrop, MA

Average rainfall days in December - Winthrop, MA
  • 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 January (7.9 days).

Average snowfall in December
Winthrop, MA

Average snowfall in December - Winthrop, MA
  • Average snowfall in December: 2.83"

The month with the highest snowfall is February (4.72").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Winthrop, MA

Average snowfall days in December - Winthrop, MA
  • Average snowfall days in December: 5.2 days

The months with the highest number of snowfall days are January and February (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average sea temperature in December
Winthrop, MA

Average sea temperature in December - Winthrop, MA
  • Average sea temperature in December: 46.3°F

The best month for swimming (with the highest average sea temperature) is August (67.6°F).
The coldest month (with the lowest average sea temperature) is March (38.8°F).

Average daylight in December /
Average sunshine in December
Winthrop, MA

Average daylight in December / Average sunshine in December - Winthrop, MA
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in December: 4h and 4min

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in December
Winthrop, MA

Average sunshine days in December - Winthrop, MA
  • Average sunshine days in December: 16.5 days

The month with the most sunshine days is September (17.7 days).
The month with the least sunshine days is April (13 days).

Average UV index in December
Winthrop, MA

Average UV index in December - Winthrop, MA
  • 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
Winthrop, MA

Average cloud cover in December - Winthrop, MA
  • Average cloud cover in December: 48

The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 32).

Average visibility in December
Winthrop, MA

Average visibility in December - Winthrop, MA
  • 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).

Winthrop, Massachusetts, USA

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