December weather forecast and climate
Mount Shasta, CA

The Lake Siskiyou on the base of Mount Shasta in California, and a view of the planted forest, the far suspension bridge, and snowy mountain peak
The Lake Siskiyou on the base of Mount Shasta in California, and a view of the planted forest, the far suspension bridge, and snowy mountain peak

Weather in December

The first month of the winter, December, is also a wintry month in Mount Shasta, California, with average temperature fluctuating between 40.8°F (4.9°C) and 27.1°F (-2.7°C).

Temperature

With an average high-temperature of 40.8°F (4.9°C) and an average low-temperature of 27.1°F (-2.7°C), December is the coldest month.

Humidity

In Mount Shasta, the average relative humidity is 79%.

Rainfall

In Mount Shasta, during 9.5 rainfall days, 4.02" (102mm) of precipitation is typically accumulated. Throughout the year, there are 90.7 rainfall days, and 26.38" (670mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall in Mount Shasta, California. In December, in Mount Shasta, it is snowing for 10.9 days. Throughout December, 12.68" (322mm) of snow is accumulated. In Mount Shasta, during the entire year, snow falls for 50.2 days, and aggregates up to 81.42" (2068mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9.2h of daylight.

Sunshine

December has the least sunshine of the year in Mount Shasta, with an average of 5.4h of sunshine.

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 unsafe exposure to the UV radiation for the ordinary person.
Note: The daily maximum UV index of 2 interpret into the following advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the coldest month in Mount Shasta?

December is the coldest month, with an average high-temperature of 40.8°F (4.9°C) and an average low-temperature of 27.1°F (-2.7°C).

What is the temperature in December in Mount Shasta?

In Mount Shasta, California, in December, the average high-temperature is 40.8°F (4.9°C), and the average low-temperature is 27.1°F (-2.7°C).

What is the average humidity in December in Mount Shasta?

In Mount Shasta, California, the average relative humidity in December is 79%.

How much does it rain in Mount Shasta in December?

In Mount Shasta, in December, it is raining for 9.5 days, with typically 4.02" (102mm) of accumulated precipitation.

How much does it snow in Mount Shasta in December?

In Mount Shasta, during December, snow falls for 10.9 days and regularly aggregates up to 12.68" (322mm) of snow.

What is the month with the shortest days in Mount Shasta?

December has the shortest days of the year in Mount Shasta, with an average of 9.2h of daylight.

How many hours of daylight does Mount Shasta have in December?

In Mount Shasta, California, the average length of the day in December is 9.2h.

What is the month with the least sunshine in Mount Shasta?

December has the least sunshine of the year in Mount Shasta, with an average of 5.4h of sunshine.

How long on average sun shines in December in Mount Shasta?

In December, the average sunshine in Mount Shasta is 5.4h.

What is the month with the lowest UV index in Mount Shasta?

Months with the lowest UV index in Mount Shasta, California, are January through March, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December in Mount Shasta?

The average daily maximum UV index in December in Mount Shasta, California, is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to the UV radiation.

Average temperature in December
Mount Shasta, CA

Average temperature in December - Mount Shasta, CA
  • Average high temperature in December: 40.8°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is December (40.8°F).

  • Average low temperature in December: 27.1°F

The month with the highest average low temperature is July (52.2°F).
The coldest month (with the lowest average low temperature) is December (27.1°F).

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Average pressure in December
Mount Shasta, CA

Average pressure in December - Mount Shasta, CA
  • Average pressure in December: 30.14"

The month with the highest atmospheric pressure is January (30.17").
Months with the lowest atmospheric pressure are June and August (29.94").

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Average wind speed in December
Mount Shasta, CA

Average wind speed in December - Mount Shasta, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is March (5.8mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

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Average humidity in December
Mount Shasta, CA

Average humidity in December - Mount Shasta, CA
  • Average humidity in December: 79%

The month with the highest relative humidity is March (81%).
The month with the lowest relative humidity is August (45%).

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Average rainfall in December
Mount Shasta, CA

Average rainfall in December - Mount Shasta, CA
  • Average rainfall in December: 4.02"

The wettest month (with the highest rainfall) is March (4.69").
The driest month (with the least rainfall) is July (0.16").

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Average rainfall days in December
Mount Shasta, CA

Average rainfall days in December - Mount Shasta, CA
  • Average rainfall days in December: 9.5 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (2.3 days).

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Average snowfall in December
Mount Shasta, CA

Average snowfall in December - Mount Shasta, CA
  • Average snowfall in December: 12.68"

The month with the highest snowfall is January (19.21").
Months with the least snowfall are June, July and August (0").

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Average snowfall days in December
Mount Shasta, CA

Average snowfall days in December - Mount Shasta, CA
  • Average snowfall days in December: 10.9 days

The month with the highest number of snowfall days is December (10.9 days).
Months with the least snowfall days are July and August (0 days).

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Average daylight in December /
Average sunshine in December
Mount Shasta, CA

Average daylight in December / Average sunshine in December - Mount Shasta, CA
  • Average daylight in December: 9.2h

The month with the longest days is June (Average daylight: 15.1h).
The month with the shortest days is December (Average daylight: 9.2h).

  • Average sunshine in December: 5.4h

The month with the most sunshine is July (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 5.4h).

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Average sunshine days in December
Mount Shasta, CA

Average sunshine days in December - Mount Shasta, CA
  • Average sunshine days in December: 14.9 days

Months with the most sunshine days are July and August (25.7 days).
The month with the least sunshine days is March (12.3 days).

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Average UV index in December
Mount Shasta, CA

Average UV index in December - Mount Shasta, CA
  • Average UV index in December: 2

Months with the highest UV index are June and July (UV index 6).
Months with the lowest UV index are January, February, March, November and December (UV index 2).

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Average cloud cover in December
Mount Shasta, CA

Average cloud cover in December - Mount Shasta, CA
  • Average cloud cover in December: 43

The month with the most cloud cover is March (Cloud cover 45).
The month with the least cloud cover is August (Cloud cover 6).

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Average visibility in December
Mount Shasta, CA

Average visibility in December - Mount Shasta, CA
  • Average visibility in December: 5mi

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

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