December weather forecast
Mammoth, WY

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Weather in December

December, the first month of the winter in Mammoth, is also a subzero cold month, with an average temperature ranging between max 20.1°F (-6.6°C) and min 4.8°F (-15.1°C).

Temperature

With average high and low temperatures of 20.1°F (-6.6°C) and 4.8°F (-15.1°C) respectively, December is Mammoth's coldest month.

Humidity

In December, the average relative humidity in Mammoth is 93%.

Rainfall

In Mammoth, in December, it is raining for 4 days, with typically 1.97" (50mm) of accumulated precipitation. Throughout the year, there are 109.2 rainfall days, and 23.15" (588mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Mammoth, Wyoming, are January through July, September through December. In Mammoth, in December, snow falls for 23.5 days, with typically accumulated 16.38" (416mm) of snow. In Mammoth, during the entire year, snow falls for 159.3 days and aggregates up to 120.47" (3060mm) of snow.

Daylight

The month with the shortest days in Mammoth, Wyoming, is December, with an average of 8h and 48min of daylight.
On the first day of the month, sunrise is at 7:41 am and sunset at 4:42 pm. On the last day of December, sunrise is at 8:00 am and sunset at 4:51 pm MST.

Sunshine

January, February and December, with an average of 3.3h of sunshine, are months with the least sunshine in Mammoth.

UV index

January through April, October through December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to UV radiation for ordinary individuals.
Note: During December, 1 as the daily maximum UV index converts into the following advice:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Stay sun-safe with clothing that is both closely woven and worn loosely. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest in Mammoth?

December, known for its average high temperature of 20.1°F (-6.6°C) and an average low temperature of 4.8°F (-15.1°C), is the coldest month in Mammoth.

How cold is December in Mammoth?

The average high-temperature, in December, in Mammoth, is 20.1°F (-6.6°C), while the average low-temperature is 4.8°F (-15.1°C).

What is the average humidity in December in Mammoth?

In December, the average relative humidity in Mammoth is 93%.

How many days does it rain in December in Mammoth?

In December, in Mammoth, the rain falls for 4 days. Throughout December, 1.97" (50mm) of precipitation is accumulated.

How many days does it snow in December in Mammoth?

In December, it is snowing for 23.5 days. Throughout December, 16.38" (416mm) of snow is accumulated.

What is the month with the shortest days in Mammoth?

With an average of 8h and 48min of daylight, December has the shortest days of the year.

How many hours of daylight does Mammoth have in December?

The average day length in December in Mammoth, Wyoming, is 8h and 50min.

When are sunrise and sunset in December in Mammoth?

On the first day of December in Mammoth, Wyoming, sunrise is at 7:41 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 8:00 am and sunset at 4:51 pm MST.

What is the month with the least sunshine in Mammoth?

January, February and December, with an average of 3.3h of sunshine, are months with the least sunshine in Mammoth.

How many hours of sunshine does Mammoth have in December?

In December, the average sunshine duration is 3.3h.

When is the lowest UV index in Mammoth?

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

How high is the UV index in December in Mammoth?

In Mammoth, Wyoming, 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 the Sun's 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, WY

Average temperature in December - Mammoth, WY
  • Average high temperature in December: 20.1°F

The warmest month (with the highest average high temperature) is July (72.9°F).
The month with the lowest average high temperature is December (20.1°F).

  • Average low temperature in December: 4.8°F

The month with the highest average low temperature is August (43.7°F).
The coldest month (with the lowest average low temperature) is December (4.8°F).

Average pressure in December
Mammoth, WY

Average pressure in December - Mammoth, WY
  • Average pressure in December: 30.23"Hg

The month with the highest atmospheric pressure is January (30.24"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in December
Mammoth, WY

Average wind speed in December - Mammoth, WY
  • Average wind speed in December: 6.2mph

The windiest month (with the highest average wind speed) is June (6.8mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).

Average humidity in December
Mammoth, WY

Average humidity in December - Mammoth, WY
  • Average humidity in December: 93%

The month with the highest relative humidity is February (95%).
The month with the lowest relative humidity is August (50%).

Average rainfall in December
Mammoth, WY

Average rainfall in December - Mammoth, WY
  • Average rainfall in December: 1.97"

The wettest month (with the highest rainfall) is May (2.8").
The driest month (with the least rainfall) is July (0.91").

Average rainfall days in December
Mammoth, WY

Average rainfall days in December - Mammoth, WY
  • Average rainfall days in December: 4 days

The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (2.2 days).

Average snowfall in December
Mammoth, WY

Average snowfall in December - Mammoth, WY
  • Average snowfall in December: 16.38"

The month with the highest snowfall is February (17.83").
The month with the least snowfall is August (0").

Average snowfall days in December
Mammoth, WY

Average snowfall days in December - Mammoth, WY
  • Average snowfall days in December: 23.5 days

The month with the highest number of snowfall days is March (24.4 days).
The months with the least snowfall days are July and August (0.2 days).

Average daylight in December /
Average sunshine in December
Mammoth, WY

Average daylight in December / Average sunshine in December - Mammoth, WY
  • Average daylight in December: 8h and 5min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in December: 3h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 3h and 18min).

Average sunshine days in December
Mammoth, WY

Average sunshine days in December - Mammoth, WY
  • Average sunshine days in December: 8.2 days

The months with the most sunshine days are July and September (14.7 days).
The month with the least sunshine days is February (5.3 days).

Average UV index in December
Mammoth, WY

Average UV index in December - Mammoth, WY
  • Average UV index in December: 1

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 1).

Average cloud cover in December
Mammoth, WY

Average cloud cover in December - Mammoth, WY
  • Average cloud cover in December: 72

The month with the most cloud cover is February (Cloud cover 76).
The month with the least cloud cover is July (Cloud cover 16).

Average visibility in December
Mammoth, WY

Average visibility in December - Mammoth, WY
  • Average visibility in December: 3mi

The months with the highest visibility are June, July, August and September (6mi).
The months with the lowest visibility are January, February, March and December (3mi).

Mammoth, Wyoming, USA

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