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, Wisconsin, experiences a temperature shift at the start of December, with average high-temperatures adjusting from an icy 41.7°F (5.4°C) in November to a subzero cold 28.8°F (-1.8°C). In Green Bay, the nocturnal temperatures throughout December show a marginal dip from the daytime averages, settling at a still freezing cold 19.9°F (-6.7°C).

Humidity

The average relative humidity in December is 85%.

Rainfall

In Green Bay, in December, it is raining for 6.5 days, with typically 1.73" (44mm) of accumulated precipitation. Throughout the year, there are 130.8 rainfall days, and 24.8" (630mm) of precipitation is accumulated.

Snowfall

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

Ocean temperature

In Green Bay, the average seawater temperature in December is 41.5°F (5.3°C).
Note: Engaging in a swim in 41.5°F (5.3°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 8h and 54min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:09 am and sunset at 4:13 pm. On the last day of December, sunrise is at 7:28 am and sunset at 4:22 pm CST.

Sunshine

The average sunshine in December is 3.6h.

UV index

January, February, November and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 1 during December, leads to the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December in Green Bay?

In December, the average high-temperature and low-temperature are 28.8°F (-1.8°C) and 19.9°F (-6.7°C) respectively.

What is the average humidity in December?

In December, the average relative humidity is 85%.

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

In December, in Green Bay, 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, in December, snow falls for 13.6 days, with typically accumulated 4.76" (121mm) of snow.

What is the water temperature in December?

In Green Bay, the average seawater temperature in December is 41.5°F (5.3°C). Swimming in 41.5°F (5.3°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?

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

What is the average length of the day in December?

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

When are sunrise and sunset in December?

On the first day of December, 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 many hours of sunshine does Green Bay have in December?

In Green Bay, the average sunshine duration in December is 3.6h.

What are the months with the lowest UV index?

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

What is the UV index intensity in December?

The average daily maximum UV index in December is 1. 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
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).

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).

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).

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%).

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").

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).

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").

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).

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).

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).

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).

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).

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).

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).

Green Bay, Wisconsin, USA

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