December weather forecast
Grass Range, MT

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Weather in December

The first month of the winter, December, is still a freezing cold month in Grass Range, Montana, with an average temperature ranging between max 29.1°F (-1.6°C) and min 16°F (-8.9°C).

Temperature

The months of February and December are noted for their lowest temperatures, with an average high-temperature of 29.1°F (-1.6°C).

Humidity

The average relative humidity in December is 77%.

Rainfall

The month with the least rainfall is December, when the rain falls for 6 days and typically collects 0.71" (18mm) of precipitation.

Snowfall

January through June, September through December are months with snowfall. In Grass Range, during December, snow falls for 13.5 days and regularly aggregates up to 4.88" (124mm) of snow. In Grass Range, during the entire year, snow falls for 83.4 days and aggregates up to 45.51" (1156mm) of snow.

Daylight

With an average of 8h and 36min of daylight, December has the shortest days of the year in Grass Range.
On the first day of the month, sunrise is at 7:41 am and sunset at 4:27 pm. On the last day of December, sunrise is at 8:00 am and sunset at 4:36 pm MST.

Sunshine

The average sunshine in December in Grass Range is 5.6h.

UV index

January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Grass Range. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum UV index of 2 during December translates into these guidelines:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year in Grass Range?

Grass Range's coldest period falls in February and December, when the average high-temperatures ascend to 29.1°F (-1.6°C).

How cold is it in Grass Range in December?

In Grass Range, in December, the average high-temperature is 29.1°F (-1.6°C), and the average low-temperature is 16°F (-8.9°C).

What is the average humidity in December in Grass Range?

The average relative humidity in December in Grass Range is 77%.

What is the driest month in Grass Range?

December is the month with the least rainfall in Grass Range. Rain falls for 6 days and accumulates 0.71" (18mm) of precipitation.

How many days does it rain in December in Grass Range?

In Grass Range, in December, it is raining for 6 days, with typically 0.71" (18mm) of accumulated precipitation.

How many days does it snow in December in Grass Range?

In Grass Range, Montana, in December, during 13.5 snowfall days, 4.88" (124mm) of snow is typically accumulated.

What is the month with the shortest days in Grass Range?

December has the shortest days of the year in Grass Range, with an average of 8h and 36min of daylight.

How many hours of daylight does Grass Range have in December?

The average day length in December is 8h and 35min.

What time are sunrise and sunset in December in Grass Range?

In December, on the first day of the month, sunrise is at 7:41 am and sunset at 4:27 pm. On the last day of the month, in Grass Range, Montana, sunrise is at 8:00 am and sunset at 4:36 pm MST.

How long on average sun shines in December in Grass Range?

In December, the average sunshine duration is 5.6h.

When is the lowest UV index in Grass Range?

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

How high is the UV index in December in Grass Range?

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low health risk 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
Grass Range, MT

Average temperature in December - Grass Range, MT
  • Average high temperature in December: 29.1°F

The warmest month (with the highest average high temperature) is July (78.8°F).
The months with the lowest average high temperature are February and December (29.1°F).

  • Average low temperature in December: 16°F

The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).

Average pressure in December
Grass Range, MT

Average pressure in December - Grass Range, MT
  • Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).

Average wind speed in December
Grass Range, MT

Average wind speed in December - Grass Range, MT
  • Average wind speed in December: 9.5mph

The windiest months (with the highest average wind speed) are January, April and October (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).

Average humidity in December
Grass Range, MT

Average humidity in December - Grass Range, MT
  • Average humidity in December: 77%

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (47%).

Average rainfall in December
Grass Range, MT

Average rainfall in December - Grass Range, MT
  • Average rainfall in December: 0.71"

The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (0.71").

Average rainfall days in December
Grass Range, MT

Average rainfall days in December - Grass Range, MT
  • Average rainfall days in December: 6 days

The month with the highest number of rainy days is May (19.3 days).
The month with the least rainy days is January (5.4 days).

Average snowfall in December
Grass Range, MT

Average snowfall in December - Grass Range, MT
  • Average snowfall in December: 4.88"

The month with the highest snowfall is April (9.13").
The months with the least snowfall are July and August (0").

Average snowfall days in December
Grass Range, MT

Average snowfall days in December - Grass Range, MT
  • Average snowfall days in December: 13.5 days

The month with the highest number of snowfall days is February (15.2 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in December /
Average sunshine in December
Grass Range, MT

Average daylight in December / Average sunshine in December - Grass Range, MT
  • Average daylight in December: 8h and 4min

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

  • Average sunshine in December: 5h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).

Average sunshine days in December
Grass Range, MT

Average sunshine days in December - Grass Range, MT
  • Average sunshine days in December: 16 days

The month with the most sunshine days is September (19.3 days).
The month with the least sunshine days is April (8.3 days).

Average UV index in December
Grass Range, MT

Average UV index in December - Grass Range, 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, April, October, November and December (UV index 2).

Average cloud cover in December
Grass Range, MT

Average cloud cover in December - Grass Range, MT
  • Average cloud cover in December: 41

The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 16).

Average visibility in December
Grass Range, MT

Average visibility in December - Grass Range, 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).

Grass Range, Montana, USA

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