December weather forecast
Sun River, MT

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Weather in December

December, the first month of the winter in Sun River, is also a subzero cold month, with an average temperature varying between 29.5°F (-1.4°C) and 17.4°F (-8.1°C).

Temperature

Sun River records the coldest temperatures in December, averaging a high of 29.5°F (-1.4°C) and a low of 17.4°F (-8.1°C).

Humidity

In Sun River, the average relative humidity in December is 77%.

Rainfall

In Sun River, in December, during 4.9 rainfall days, 0.67" (17mm) of precipitation is typically accumulated. Throughout the year, in Sun River, there are 112.8 rainfall days, and 12.95" (329mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall in Sun River, Montana. In December, it is snowing for 12.4 days. Throughout December, 4.37" (111mm) of snow is accumulated. In Sun River, during the entire year, snow falls for 69.4 days and aggregates up to 35.35" (898mm) of snow.

Daylight

The month with the shortest days is December, with an average of 8h and 30min of daylight.
On the first day of December, sunrise is at 7:54 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 8:14 am and sunset at 4:45 pm MST.

Sunshine

January and December, with an average of 5.4h of sunshine, are months with the least sunshine.

UV index

The months with the lowest UV index are January through March, October through December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 2 in December translates into these instructions:
Most individuals can handle sun exposure for up to an hour without burning, but children must always be shielded from sun exposure. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
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Frequently asked questions

What month is the coldest in Sun River?

December is the coldest month, with the temperature often reaching an average high of 29.5°F (-1.4°C) and an average low of 17.4°F (-8.1°C).

How cold is December in Sun River?

The average high-temperature, in December, in Sun River, is 29.5°F (-1.4°C), while the average low-temperature is 17.4°F (-8.1°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which factors the actual air temperature with the relative humidity, in August is estimated at 80.6°F (27°C).

What is the average humidity in December in Sun River?

In December, the average relative humidity is 77%.

How much does it rain in Sun River in December?

In Sun River, Montana, in December, during 4.9 rainfall days, 0.67" (17mm) of precipitation is typically accumulated.

How many days does it snow in December in Sun River?

In Sun River, Montana, in December, snow falls for 12.4 days, with typically accumulated 4.37" (111mm) of snow.

What is the month with the shortest days in Sun River?

The month with the shortest days in Sun River, Montana, is December, with an average of 8h and 30min of daylight.

What is the average length of the day in December in Sun River?

In December, the average day length in Sun River, Montana, is 8h and 31min.

What time are sunrise and sunset in December in Sun River?

In December, on the first day of the month, sunrise is at 7:54 am and sunset at 4:37 pm. On the last day of the month, sunrise is at 8:14 am and sunset at 4:45 pm MST.

What are the months with the least sunshine in Sun River?

The months with the least sunshine are January and December, with an average of 5.4h of sunshine.

How many hours of sunshine does Sun River have in December?

The average sunshine duration in December in Sun River, Montana, is 5.4h.

What are the months with the lowest UV index in Sun River?

The months with the lowest UV index in Sun River, Montana, are January through March, October through December, with an average maximum UV index of 2.

What is the UV index reading in December in Sun River?

In Sun River, Montana, the average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health 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
Sun River, MT

Average temperature in December - Sun River, MT
  • Average high temperature in December: 29.5°F

The warmest month (with the highest average high temperature) is July (82.2°F).
The month with the lowest average high temperature is December (29.5°F).

  • Average low temperature in December: 17.4°F

The month with the highest average low temperature is August (56.7°F).
The coldest month (with the lowest average low temperature) is December (17.4°F).

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Average pressure in December
Sun River, MT

Average pressure in December - Sun River, MT
  • Average pressure in December: 30.14"Hg

The months with the highest atmospheric pressure are January and December (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

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Average wind speed in December
Sun River, MT

Average wind speed in December - Sun River, MT
  • Average wind speed in December: 10.4mph

The windiest months (with the highest average wind speed) are January and November (10.7mph).
The calmest month (with the lowest average wind speed) is August (7.3mph).

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Average humidity in December
Sun River, MT

Average humidity in December - Sun River, MT
  • Average humidity in December: 77%

The month with the highest relative humidity is January (78%).
The month with the lowest relative humidity is August (41%).

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Average rainfall in December
Sun River, MT

Average rainfall in December - Sun River, MT
  • Average rainfall in December: 0.67"

The wettest month (with the highest rainfall) is June (2.05").
The driest months (with the least rainfall) are January and July (0.63").

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Average rainfall days in December
Sun River, MT

Average rainfall days in December - Sun River, MT
  • Average rainfall days in December: 4.9 days

The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is January (4.8 days).

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Average snowfall in December
Sun River, MT

Average snowfall in December - Sun River, MT
  • Average snowfall in December: 4.37"

The month with the highest snowfall is February (6.34").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in December
Sun River, MT

Average snowfall days in December - Sun River, MT
  • Average snowfall days in December: 12.4 days

The month with the highest number of snowfall days is February (14.4 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
Sun River, MT

Average daylight in December / Average sunshine in December - Sun River, MT
  • Average daylight in December: 8h and 3min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in December: 5h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The months with the least sunshine are January and December (Average sunshine: 5h and 24min).

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Average sunshine days in December
Sun River, MT

Average sunshine days in December - Sun River, MT
  • Average sunshine days in December: 17.7 days

The month with the most sunshine days is September (18.8 days).
The month with the least sunshine days is April (10.3 days).

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Average UV index in December
Sun River, MT

Average UV index in December - Sun River, MT
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

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Average cloud cover in December
Sun River, MT

Average cloud cover in December - Sun River, MT
  • Average cloud cover in December: 43

The month with the most cloud cover is February (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 14).

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Average visibility in December
Sun River, MT

Average visibility in December - Sun River, MT
  • 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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Sun River, Montana, USA

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