December weather forecast
Mammoth Lakes, CA

Perfect water reflections of trees, rocks, and distant mountains in the clear water of Mammoth Lakes, California
Perfect water reflections of trees, rocks, and distant mountains in the clear water of Mammoth Lakes, California

Weather in December

December, the first month of the winter in Mammoth Lakes, is still a cold month, with an average temperature fluctuating between 34.2°F (1.2°C) and 15.4°F (-9.2°C).

Temperature

In December, the average high-temperature decreases from a frosty 44.4°F (6.9°C) in November to a wintry 34.2°F (1.2°C). The average low-temperature, in December, is 15.4°F (-9.2°C).

Humidity

In December, the average relative humidity is 71%.

Rainfall

In Mammoth Lakes, during 4.8 rainfall days, 0.63" (16mm) of precipitation is typically accumulated. Throughout the year, there are 47.7 rainfall days, and 4.92" (125mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through June, September through December. In Mammoth Lakes, during December, snow falls for 9.5 days and regularly aggregates up to 4.92" (125mm) of snow. Throughout the year, in Mammoth Lakes, California, there are 60.8 snowfall days, and 28.58" (726mm) of snow is accumulated.

Daylight

The month with the shortest days in Mammoth Lakes is December, with an average of 9h and 37min of daylight.
On the first day of December in Mammoth Lakes, sunrise is at 6:52 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 4:47 pm PST.

Sunshine

In December, the average sunshine is 6.4h.

UV index

The months with the lowest UV index are January through April, October through December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 2 in December interpret into the following advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. 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 the 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 average humidity in December in Mammoth Lakes?

In December, the average relative humidity in Mammoth Lakes, California, is 71%.

How much does it rain in Mammoth Lakes in December?

In Mammoth Lakes, during December, the rain falls for 4.8 days and regularly aggregates up to 0.63" (16mm) of precipitation.

How much does it snow in Mammoth Lakes in December?

In Mammoth Lakes, during December, snow falls for 9.5 days and regularly aggregates up to 4.92" (125mm) of snow.

What is the month with the shortest days in Mammoth Lakes?

The month with the shortest days in Mammoth Lakes, California, is December, with an average of 9h and 37min of daylight.

How many hours of daylight does Mammoth Lakes have in December?

In December, the average day length in Mammoth Lakes, California, is 9h and 37min.

When are sunrise and sunset in December in Mammoth Lakes?

On the first day of December, sunrise is at 6:52 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 4:47 pm PST.

How long on average sun shines in December in Mammoth Lakes?

The average sunshine duration in December in Mammoth Lakes, California, is 6.4h.

What is the month with the lowest UV index in Mammoth Lakes?

The months with the lowest UV index in Mammoth Lakes are January through April, October through December, with an average maximum UV index of 2.

How high is the UV index in December in Mammoth Lakes?

The average daily maximum UV index in December in Mammoth Lakes, California, is 2. A UV Index value of 2, and less, symbolizes a low health threat 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
Mammoth Lakes, CA

Average temperature in December - Mammoth Lakes, CA
  • Average high temperature in December: 34.2°F

The warmest month (with the highest average high temperature) is July (73.4°F).
The month with the lowest average high temperature is February (34°F).

  • Average low temperature in December: 15.4°F

The month with the highest average low temperature is July (48.2°F).
The coldest month (with the lowest average low temperature) is February (14.9°F).

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Average pressure in December
Mammoth Lakes, CA

Average pressure in December - Mammoth Lakes, CA
  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

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Average wind speed in December
Mammoth Lakes, CA

Average wind speed in December - Mammoth Lakes, CA
  • Average wind speed in December: 6.1mph

The windiest month (with the highest average wind speed) is March (6.9mph).
The calmest months (with the lowest average wind speed) are July and August (4.9mph).

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Average humidity in December
Mammoth Lakes, CA

Average humidity in December - Mammoth Lakes, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is February (76%).
The month with the lowest relative humidity is August (34%).

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Average rainfall in December
Mammoth Lakes, CA

Average rainfall in December - Mammoth Lakes, CA
  • Average rainfall in December: 0.63"

The wettest month (with the highest rainfall) is February (0.94").
The driest months (with the least rainfall) are August and October (0.08").

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Average rainfall days in December
Mammoth Lakes, CA

Average rainfall days in December - Mammoth Lakes, CA
  • Average rainfall days in December: 4.8 days

The month with the highest number of rainy days is April (6.3 days).
The month with the least rainy days is August (1.8 days).

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Average snowfall in December
Mammoth Lakes, CA

Average snowfall in December - Mammoth Lakes, CA
  • Average snowfall in December: 4.92"

The month with the highest snowfall is February (5.67").
The months with the least snowfall are July and August (0").

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Average snowfall days in December
Mammoth Lakes, CA

Average snowfall days in December - Mammoth Lakes, CA
  • Average snowfall days in December: 9.5 days

The month with the highest number of snowfall days is March (11.3 days).
The months with the least snowfall days are July and August (0 days).

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Average daylight in December /
Average sunshine in December
Mammoth Lakes, CA

Average daylight in December / Average sunshine in December - Mammoth Lakes, CA
  • Average daylight in December: 9h and 37min

The month with the longest days is June (Average daylight: 14h and 44min).
The month with the shortest days is December (Average daylight: 9h and 37min).

  • Average sunshine in December: 6h and 24min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 6h and 18min).

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Average sunshine days in December
Mammoth Lakes, CA

Average sunshine days in December - Mammoth Lakes, CA
  • Average sunshine days in December: 21.3 days

The month with the most sunshine days is October (27.3 days).
The month with the least sunshine days is March (18.2 days).

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Average UV index in December
Mammoth Lakes, CA

Average UV index in December - Mammoth Lakes, CA
  • Average UV index in December: 2

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

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Average cloud cover in December
Mammoth Lakes, CA

Average cloud cover in December - Mammoth Lakes, CA
  • Average cloud cover in December: 29

The month with the most cloud cover is March (Cloud cover 30).
The month with the least cloud cover is August (Cloud cover 7).

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Average visibility in December
Mammoth Lakes, CA

Average visibility in December - Mammoth Lakes, CA
  • Average visibility in December: 6mi

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

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