December weather forecast
Juneau, AK

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Blooming fireweed in Juneau, Alaska with snowy mountain peaks in the distance
Blooming fireweed in Juneau, Alaska with snowy mountain peaks in the distance

Weather in December

December welcomes winter back to Juneau with cold temperatures and heavy snowfall. An average accumulation of 62.8" (1595mm) of snow, the highest after January, blankets the city. While temperatures mirror those in January, daylight hours are at their shortest for the year. The sea temperature drops to 43.3°F (6.3°C), marking a distinct difference compared to the warmer months. With a strong wind gust of 11.3mph (18.2km/h) providing an additional chill to the air, December paints a serene and quiet winter landscape in Juneau.

Temperature

The months of January and December bring the lowest temperatures, averaging a high of 25.7°F (-3.5°C).

Humidity

The average relative humidity in December is 90%.

Rainfall

In Juneau, in December, during 5.8 rainfall days, 8.98" (228mm) of precipitation is typically accumulated. In Juneau, during the entire year, the rain falls for 172.4 days and collects up to 85.87" (2181mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall in Juneau, Alaska. The month with the most snowfall is December, when snow falls for 21.8 days and typically aggregates up to 62.8" (1595mm) of snow.

Ocean temperature

In Juneau, in December, the average water temperature is 43.3°F (6.3°C).
Note: It is life-risking to swim in 43.3°F (6.3°C). Briefly staying in 55.4°F (13°C) waters feels unsettling, and temperatures below 50°F (10°C) might result in cold shock and loss of breath control, hinging on personal endurance.

Daylight

With an average of 6h and 30min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 8:21 am and sunset at 3:12 pm. On the last day of December, sunrise is at 8:45 am and sunset at 3:16 pm AKST.

Sunshine

In Juneau, the average sunshine in December is 2.9h.

UV index

The months with the lowest UV index are January, April, October through December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, a daily UV index of 1 turns into the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.

Frequently asked questions

What part of the year is the coldest?

The lowest level of Juneau's temperatures is noted during January and December, averaging a high-temperature of 25.7°F (-3.5°C).

How cold is December?

In Juneau, 25.7°F (-3.5°C) is the average high-temperature and 19°F (-7.2°C) is the average low-temperature during December.

What is the average humidity in December?

The average relative humidity in December is 90%.

How many days does it rain in December?

In December, the rain falls for 5.8 days. Throughout December, 8.98" (228mm) of precipitation is accumulated.

When does it snow the most?

December is the month with the most snowfall. Snow falls for 21.8 days and accumulates 62.8" (1595mm) of snow.

How many days does it snow in December?

In December, it is snowing for 21.8 days. Throughout December, 62.8" (1595mm) of snow is accumulated.

How cold is the water in December?

In Juneau, in December, the average water temperature is 43.3°F (6.3°C). Swimming in 43.3°F (6.3°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 6h and 30min of daylight, December has the shortest days of the year.

How many hours of daylight does Juneau have in December?

In December, the average day length is 6h and 31min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 8:21 am and sunset at 3:12 pm. On the last day of the month, sunrise is at 8:45 am and sunset at 3:16 pm AKST.

How many hours of sunshine does Juneau have in December?

The average sunshine duration in December is 2.9h.

When is the lowest UV index?

The months with the lowest UV index are January, April, October through December, with an average maximum UV index of 1.

How high is the UV index in December?

The average daily maximum UV index in December is 1. A UV Index of 2, and less, symbolizes a minimal health vulnerability from 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
Juneau, AK

Average temperature in December - Juneau, AK
  • Average high temperature in December: 25.7°F

The warmest month (with the highest average high temperature) is July (55.8°F).
The months with the lowest average high temperature are January and December (25.7°F).

  • Average low temperature in December: 19°F

The month with the highest average low temperature is July (45.1°F).
The coldest month (with the lowest average low temperature) is February (17.1°F).

Average pressure in December
Juneau, AK

Average pressure in December - Juneau, AK
  • Average pressure in December: 29.87"Hg

The month with the highest atmospheric pressure is July (30.03"Hg).
The month with the lowest atmospheric pressure is November (29.8"Hg).

Average wind speed in December
Juneau, AK

Average wind speed in December - Juneau, AK
  • Average wind speed in December: 6.5mph

The windiest month (with the highest average wind speed) is January (6.9mph).
The calmest months (with the lowest average wind speed) are June and July (3.7mph).

Average humidity in December
Juneau, AK

Average humidity in December - Juneau, AK
  • Average humidity in December: 90%

The month with the highest relative humidity is January (92%).
The month with the lowest relative humidity is May (86%).

Average rainfall in December
Juneau, AK

Average rainfall in December - Juneau, AK
  • Average rainfall in December: 8.98"

The wettest month (with the highest rainfall) is October (9.88").
The driest month (with the least rainfall) is May (4.13").

Average rainfall days in December
Juneau, AK

Average rainfall days in December - Juneau, AK
  • Average rainfall days in December: 5.8 days

The month with the highest number of rainy days is September (21.9 days).
The month with the least rainy days is February (4.8 days).

Average snowfall in December
Juneau, AK

Average snowfall in December - Juneau, AK
  • Average snowfall in December: 62.8"

The month with the highest snowfall is December (62.8").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Juneau, AK

Average snowfall days in December - Juneau, AK
  • Average snowfall days in December: 21.8 days

The month with the highest number of snowfall days is January (21.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average sea temperature in December
Juneau, AK

Average sea temperature in December - Juneau, AK
  • Average sea temperature in December: 43.3°F

The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is March (40.3°F).

Average daylight in December /
Average sunshine in December
Juneau, AK

Average daylight in December / Average sunshine in December - Juneau, AK
  • Average daylight in December: 6h and 3min

The month with the longest days is June (Average daylight: 18h and 12min).
The month with the shortest days is December (Average daylight: 6h and 30min).

  • Average sunshine in December: 2h and 5min

The month with the most sunshine is June (Average sunshine: 6h and 24min).
The month with the least sunshine is November (Average sunshine: 2h and 36min).

Average sunshine days in December
Juneau, AK

Average sunshine days in December - Juneau, AK
  • Average sunshine days in December: 7.6 days

The month with the most sunshine days is May (10 days).
The month with the least sunshine days is November (6.1 days).

Average UV index in December
Juneau, AK

Average UV index in December - Juneau, AK
  • Average UV index in December: 1

The months with the highest UV index are May and July (UV index 3).
The months with the lowest UV index are January, April, October, November and December (UV index 1).

Average cloud cover in December
Juneau, AK

Average cloud cover in December - Juneau, AK
  • Average cloud cover in December: 71

The months with the most cloud cover are January and November (Cloud cover 72).
The month with the least cloud cover is May (Cloud cover 61).

Average visibility in December
Juneau, AK

Average visibility in December - Juneau, AK
  • Average visibility in December: 4mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).

Juneau, Alaska, USA

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