December weather forecast
Great Falls, MT

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A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana
A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana

Weather in December

December brings in the cold winter weather and frigid temperatures. Reaching only 30°F (-1.1°C), it's one of the chilliest periods in Great Falls, Montana. The anticipated weather shift signifies a further drop in temperature as the new year approaches. Residents and travelers adapt to cold weather activities, including ice skating, snow filtering and visiting local holiday markets. Even in the biting cold, the festive spirit makes December a memorable time.

Temperature

December is the coldest month, exhibiting average temperatures of 30°F (-1.1°C) at the peak and 18.3°F (-7.6°C) at the base.

Humidity

The average relative humidity in December is 76%.

Rainfall

December is the month with the least rainfall. Rain falls for 2.7 days and accumulates 0.16" (4mm) of precipitation.

Snowfall

Months with snowfall in Great Falls are January through May, September through December. In December, it is snowing for 7.9 days. Throughout December, 1.06" (27mm) of snow is accumulated. Throughout the year, there are 45.4 snowfall days, and 11.61" (295mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 8h and 30min of daylight.
On the first day of the month, sunrise is at 7:52 am and sunset at 4:36 pm. On the last day of December, sunrise is at 8:12 am and sunset at 4:44 pm MST.

Sunshine

The months with the least sunshine are January, February and December, with an average of 5.5h of sunshine.

UV index

January through March, October through 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 vulnerability from exposure to the Sun's UV rays for average individuals.
Note: A typical high UV index of 2 in December suggests the following recommendations:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. 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. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.

Frequently asked questions

What is the coldest month?

Great Falls records the coldest temperatures in December, averaging a high of 30°F (-1.1°C) and a low of 18.3°F (-7.6°C).

How cold is it in December?

During December, Great Falls experiences an average high-temperature of 30°F (-1.1°C) and a low-temperature of 18.3°F (-7.6°C). In August, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is appraised at 80.6°F (27°C).

What is the average humidity in December?

In Great Falls, the average relative humidity in December is 76%.

What is the driest month?

December is the month with the least rainfall. Rain falls for 2.7 days and accumulates 0.16" (4mm) of precipitation.

How many days does it rain in December?

In Great Falls, during December, the rain falls for 2.7 days and regularly aggregates up to 0.16" (4mm) of precipitation.

How much does it snow in December?

In Great Falls, Montana, in December, during 7.9 snowfall days, 1.06" (27mm) of snow is typically accumulated.

What is the month with the shortest days in Great Falls?

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

How many hours of daylight does Great Falls have in December?

In December, the average day length is 8h and 31min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 7:52 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 8:12 am and sunset at 4:44 pm MST.

What are the months with the least sunshine?

January, February and December, with an average of 5.5h of sunshine, are months with the least sunshine in Great Falls.

How long on average sun shines in December?

The average sunshine duration in December is 5.5h.

What is the month with the lowest UV index?

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

How high is the UV index in December?

The average daily maximum UV index in December in Great Falls is 2. A UV Index value of 2, and less, symbolizes a low health risk 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
Great Falls, MT

Average temperature in December - Great Falls, MT
  • Average high temperature in December: 30°F

The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is December (30°F).

  • Average low temperature in December: 18.3°F

The month with the highest average low temperature is August (57.7°F).
The coldest months (with the lowest average low temperature) are February and December (18.3°F).

Average pressure in December
Great Falls, MT

Average pressure in December - Great Falls, MT
  • Average pressure in December: 30.13"Hg

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

Average wind speed in December
Great Falls, MT

Average wind speed in December - Great Falls, MT
  • Average wind speed in December: 11mph

The windiest month (with the highest average wind speed) is November (11.4mph).
The calmest month (with the lowest average wind speed) is August (7.7mph).

Average humidity in December
Great Falls, MT

Average humidity in December - Great Falls, MT
  • Average humidity in December: 76%

The month with the highest relative humidity is January (77%).
The month with the lowest relative humidity is August (40%).

Average rainfall in December
Great Falls, MT

Average rainfall in December - Great Falls, MT
  • Average rainfall in December: 0.16"

The wettest month (with the highest rainfall) is June (0.87").
The driest month (with the least rainfall) is December (0.16").

Average rainfall days in December
Great Falls, MT

Average rainfall days in December - Great Falls, MT
  • Average rainfall days in December: 2.7 days

The month with the highest number of rainy days is April (9.9 days).
The month with the least rainy days is December (2.7 days).

Average snowfall in December
Great Falls, MT

Average snowfall in December - Great Falls, MT
  • Average snowfall in December: 1.06"

The month with the highest snowfall is February (2.09").
The months with the least snowfall are June, July and August (0").

Average snowfall days in December
Great Falls, MT

Average snowfall days in December - Great Falls, MT
  • Average snowfall days in December: 7.9 days

The month with the highest number of snowfall days is February (10 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in December /
Average sunshine in December
Great Falls, MT

Average daylight in December / Average sunshine in December - Great Falls, 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 3min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 30min).

Average sunshine days in December
Great Falls, MT

Average sunshine days in December - Great Falls, MT
  • Average sunshine days in December: 22.5 days

The month with the most sunshine days is July (26.1 days).
The months with the least sunshine days are February and April (16.2 days).

Average UV index in December
Great Falls, MT

Average UV index in December - Great Falls, 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).

Average cloud cover in December
Great Falls, MT

Average cloud cover in December - Great Falls, MT
  • Average cloud cover in December: 42

The month with the most cloud cover is February (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 13).

Average visibility in December
Great Falls, MT

Average visibility in December - Great Falls, 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).

Great Falls, Montana, USA

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