Juneau
Alaska, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Juneau, AK

Blooming fireweed in Juneau, Alaska, with snowy mountain peaks in the distance
Blooming fireweed in Juneau, Alaska, with snowy mountain peaks in the distance
December, the first month of the winter, in Juneau, is also a subzero cold month, with average temperature fluctuating between 25.5°F (-3.6°C) and 25.7°F (-3.5°C).

Temperature

January and December, with an average high-temperature of 25.7°F (-3.5°C), are the coldest months.

Humidity

In December, the average relative humidity is 90%.

Rainfall

In Juneau, in December, during 5.8 rainfall days, 8.98" (228mm) of precipitation is typically accumulated. Throughout the year, in Juneau, there are 172.4 rainfall days, and 85.87" (2181mm) of precipitation is accumulated.

Snowfall

January through May, October through December are months with snowfall. 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, the average water temperature is 43.3°F (6.3°C).
Note: 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.

Daylight

With an average of 6.5h of daylight, December has the shortest days of the year in Juneau.

Sunshine

In December, the average sunshine is 2.9h.

UV index

Months with the lowest UV index are January, April, October through December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a low threat to health from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 1 in December interpret into the following advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.

What are the coldest months in Juneau?

The coldest months are January and December, with an average high-temperature of 25.7°F (-3.5°C).

What is the temperature in December in Juneau?

The average high-temperature, in December, is 25.7°F (-3.5°C), while the average low-temperature is 25.5°F (-3.6°C).

What is the average humidity in December in Juneau?

The average relative humidity in December in Juneau, Alaska, is 90%.

How much does it rain in Juneau in December?

In Juneau, in December, it is raining for 5.8 days, with typically 8.98" (228mm) of accumulated precipitation.

How much does it snow in Juneau in December?

In Juneau, during December, snow falls for 21.8 days and regularly aggregates up to 62.8" (1595mm) of snow.

When does it snow the most in Juneau?

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

What is the ocean temperature in December in Juneau?

In Juneau, the average seawater temperature in December is 43.3°F (6.3°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 Juneau?

The month with the shortest days is December, with an average of 6.5h of daylight.

What is the average length of the day in December in Juneau?

The average length of the day in December in Juneau, Alaska, is 6.5h.

How long on average sun shines in December in Juneau?

The average sunshine in December in Juneau is 2.9h.

What is the month with the lowest UV index in Juneau?

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

How high is the UV index in December in Juneau?

The average daily maximum UV index in December in Juneau, Alaska, is 1. A UV Index estimate of 2, and below, represents a low health risk from unprotected exposure to the UV radiation.
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).
Months with the lowest average high temperature are January and December (25.7°F).

  • Average low temperature in December: 25.6°F

The month with the highest average low temperature is July (50°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).

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: 8.98"

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

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 lowest number of rainy days is February (4.8 days).

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

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

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).
Months with the lowest number of snowfall days are June, July, August and September (0 days).

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: 6.5h

The month with the longest days is June (Average daylight: 18.2h).
The month with shortest days is December (Average daylight: 6.5h).

  • Average sunshine in December: 2.9h

The month with most sunshine is June (Average sunshine: 6.4h).
The month with least sunshine is November (Average sunshine: 2.6h).

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

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