December weather forecast
Green Bay, WI

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The sun setting over Green Bay in Wisconsin
The sun setting over Green Bay in Wisconsin

Weather in December

December is dominated by cold temperatures and snowfall, prepping Green Bay for the deep winter ahead. With an average snowfall of 4.76" (121mm), December ranks second in snowfall accumulation, next only to January. The daylight hours drop to a mere 8.9 hours, the shortest in the year, with sun shining for only around 3.6 hours a day on average. The sea temperature also significantly drops to 41.5°F (5.3°C), adding to the overall chill. It is worth noting that as the month progresses, the days start to gradually lengthen, offering a glimmer of the approaching spring even amid the harsh winter.

Temperature

Green Bay in December undergoes a mild reduction in the average high-temperature, shifting from November's cold 41.7°F (5.4°C) to a subzero cold 28.8°F (-1.8°C). During December, Green Bay's nights hold steady with an average temperature of 19.9°F (-6.7°C), barely dropping from the daytime highs.

Humidity

The average relative humidity in December is 85%.

Rainfall

In Green Bay, during December, the rain falls for 6.5 days and regularly aggregates up to 1.73" (44mm) of precipitation. In Green Bay, during the entire year, the rain falls for 130.8 days and collects up to 24.8" (630mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall in Green Bay. In Green Bay, during December, snow falls for 13.6 days and regularly aggregates up to 4.76" (121mm) of snow. Throughout the year, there are 63.7 snowfall days, and 23.27" (591mm) of snow is accumulated.

Ocean temperature

In December, the average ocean temperature is 41.5°F (5.3°C).
Note: Danger awaits those who swim in 41.5°F (5.3°C) without protection. Falling below 50°F (10°C) means intense cold shock and hyperventilation.

Daylight

The month with the shortest days in Green Bay is December, with an average of 8h and 54min of daylight.
On the first day of December in Green Bay, sunrise is at 7:09 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 4:22 pm CST.

Sunshine

In December, the average sunshine is 3.6h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: The maximum UV index of 1 during December leads to these instructions:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
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Frequently asked questions

How cold is December in Green Bay?

In Green Bay, 28.8°F (-1.8°C) is the average high-temperature and 19.9°F (-6.7°C) is the average low-temperature during December.

What is the average humidity in December in Green Bay?

In December, the average relative humidity in Green Bay is 85%.

How much does it rain in Green Bay in December?

In December, in Green Bay, Wisconsin, the rain falls for 6.5 days. Throughout December, 1.73" (44mm) of precipitation is accumulated.

How many days does it snow in December in Green Bay?

In Green Bay, during December, snow falls for 13.6 days and regularly aggregates up to 4.76" (121mm) of snow.

What is the water temperature in December in Green Bay?

In Green Bay, in December, the average water temperature is 41.5°F (5.3°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days in Green Bay?

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

How many hours of daylight does Green Bay have in December?

In Green Bay, the average day length in December is 8h and 54min.

When is the sunrise / sunset in December in Green Bay?

On the first day of December in Green Bay, sunrise is at 7:09 am and sunset at 4:13 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 4:22 pm CST.

How long on average sun shines in December in Green Bay?

The average sunshine duration in December in Green Bay, Wisconsin, is 3.6h.

What are the months with the lowest UV index in Green Bay?

The months with the lowest UV index in Green Bay are January, February, November and December, with an average maximum UV index of 1.

What is the UV index reading in December in Green Bay?

The average daily maximum UV index in December in Green Bay is 1. A UV Index reading of 2, and below, represents a low health risk 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
Green Bay, WI

Average temperature in December - Green Bay, WI
  • Average high temperature in December: 28.8°F

The warmest month (with the highest average high temperature) is July (78.1°F).
The month with the lowest average high temperature is January (22.6°F).

  • Average low temperature in December: 19.9°F

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (12.4°F).

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Average pressure in December
Green Bay, WI

Average pressure in December - Green Bay, WI
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is March (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in December
Green Bay, WI

Average wind speed in December - Green Bay, WI
  • Average wind speed in December: 9.9mph

The windiest months (with the highest average wind speed) are January and February (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (7.2mph).

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Average humidity in December
Green Bay, WI

Average humidity in December - Green Bay, WI
  • Average humidity in December: 85%

The month with the highest relative humidity is January (88%).
The months with the lowest relative humidity are April and May (76%).

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Average rainfall in December
Green Bay, WI

Average rainfall in December - Green Bay, WI
  • Average rainfall in December: 1.73"

The wettest month (with the highest rainfall) is May (3.31").
The driest month (with the least rainfall) is January (1.18").

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Average rainfall days in December
Green Bay, WI

Average rainfall days in December - Green Bay, WI
  • Average rainfall days in December: 6.5 days

The month with the highest number of rainy days is May (15.9 days).
The month with the least rainy days is February (3.7 days).

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Average snowfall in December
Green Bay, WI

Average snowfall in December - Green Bay, WI
  • Average snowfall in December: 4.76"

The month with the highest snowfall is February (5.79").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Green Bay, WI

Average snowfall days in December - Green Bay, WI
  • Average snowfall days in December: 13.6 days

The month with the highest number of snowfall days is January (15.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in December
Green Bay, WI

Average sea temperature in December - Green Bay, WI
  • Average sea temperature in December: 41.5°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 February (36.1°F).

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Average daylight in December /
Average sunshine in December
Green Bay, WI

Average daylight in December / Average sunshine in December - Green Bay, WI
  • 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: 3h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is February (Average sunshine: 3h and 24min).

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Average sunshine days in December
Green Bay, WI

Average sunshine days in December - Green Bay, WI
  • Average sunshine days in December: 13.9 days

The months with the most sunshine days are September and November (17 days).
The month with the least sunshine days is April (11.6 days).

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Average UV index in December
Green Bay, WI

Average UV index in December - Green Bay, WI
  • Average UV index in December: 1

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, November and December (UV index 1).

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Average cloud cover in December
Green Bay, WI

Average cloud cover in December - Green Bay, WI
  • Average cloud cover in December: 63

The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 33).

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Average visibility in December
Green Bay, WI

Average visibility in December - Green Bay, WI
  • Average visibility in December: 6mi

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

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Green Bay, Wisconsin, USA

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