December weather forecast
Grand Junction, CO

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The scenic Grand Junction in Colorado with the iconic Colorado River and high hills nearby
The scenic Grand Junction in Colorado with the iconic Colorado River and high hills nearby

Weather in December

December introduces winter in full swing, as temperatures continue to drop with a decrease to 36.3°F (2.4°C) at most. Grand Junction experiences the most snowfall during this month, ensuring a white Christmas. The city also sees the shortest daylight hours, plunging it into longer nights. Cloud coverage rises to the second highest mark of the year, wrapping the city in a winter quilt. Impending New Year celebrations see the city donning its winter-best with a white cover of snow.

Temperature

With the beginning of December, the average high-temperature shows a decrease, transitioning from a frosty 49.1°F (9.5°C) in November to an icy 36.3°F (2.4°C). During December, Grand Junction's temperature averages to a subzero cold 20.5°F (-6.4°C) at night.

Humidity

The average relative humidity in December is 69%.

Rainfall

In Grand Junction, in December, it is raining for 7.5 days, with typically 0.79" (20mm) of accumulated precipitation. Throughout the year, there are 93.6 rainfall days, and 8.46" (215mm) of precipitation is accumulated.

Snowfall

January through April, October through December are months with snowfall. December is the month with the most snowfall. Snow falls for 6.9 days and accumulates 3.74" (95mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 30min of daylight.
On the first day of the month, sunrise is at 7:14 am and sunset at 4:52 pm. On the last day of December, sunrise is at 7:33 am and sunset at 5:01 pm MST.

Sunshine

In Grand Junction, the average sunshine in December is 6.7h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The maximum UV index, 2 during December, leads to the following recommendations:
Infants, children, and people with sensitive skin should always have protection against lengthy periods of sun exposure. To guard against the harmful effects of the Sun, minimize exposure during midday. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Take to heart! Snow reflection can almost magnify the Sun's UV radiation twofold.

Frequently asked questions

How cold is it in December?

In December, the average high-temperature and low-temperature are 36.3°F (2.4°C) and 20.5°F (-6.4°C) respectively.

What is the average humidity in December?

In Grand Junction, the average relative humidity in December is 69%.

How much does it rain in December?

In Grand Junction, in December, it is raining for 7.5 days, with typically 0.79" (20mm) of accumulated precipitation.

When does it snow the most in Grand Junction?

The month with the most snowfall is December, when snow falls for 6.9 days and typically aggregates up to 3.74" (95mm) of snow.

How many days does it snow in December?

In Grand Junction, Colorado, in December, during 6.9 snowfall days, 3.74" (95mm) of snow is typically accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 30min of daylight.

What is the average length of the day in December?

In Grand Junction, the average day length in December is 9h and 29min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:14 am and sunset at 4:52 pm. On the last day of the month, in Grand Junction, sunrise is at 7:33 am and sunset at 5:01 pm MST.

How long on average sun shines in December?

In Grand Junction, the average sunshine duration in December is 6.7h.

What are the months with the lowest UV index?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December?

In Grand Junction, the average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a low health risk from unsafe 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
Grand Junction, CO

Average temperature in December - Grand Junction, CO
  • Average high temperature in December: 36.3°F

The warmest month (with the highest average high temperature) is July (86.9°F).
The month with the lowest average high temperature is January (34.9°F).

  • Average low temperature in December: 20.5°F

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (18.3°F).

Average pressure in December
Grand Junction, CO

Average pressure in December - Grand Junction, CO
  • Average pressure in December: 30.19"Hg

The month with the highest atmospheric pressure is January (30.27"Hg).
The months with the lowest atmospheric pressure are May and June (29.9"Hg).

Average wind speed in December
Grand Junction, CO

Average wind speed in December - Grand Junction, CO
  • Average wind speed in December: 4.5mph

The windiest month (with the highest average wind speed) is June (7.5mph).
The calmest month (with the lowest average wind speed) is January (4.2mph).

Average humidity in December
Grand Junction, CO

Average humidity in December - Grand Junction, CO
  • Average humidity in December: 69%

The month with the highest relative humidity is January (78%).
The month with the lowest relative humidity is June (29%).

Average rainfall in December
Grand Junction, CO

Average rainfall in December - Grand Junction, CO
  • Average rainfall in December: 0.79"

The wettest month (with the highest rainfall) is March (1.06").
The driest month (with the least rainfall) is June (0.51").

Average rainfall days in December
Grand Junction, CO

Average rainfall days in December - Grand Junction, CO
  • Average rainfall days in December: 7.5 days

The month with the highest number of rainy days is March (10.4 days).
The month with the least rainy days is November (5.5 days).

Average snowfall in December
Grand Junction, CO

Average snowfall in December - Grand Junction, CO
  • Average snowfall in December: 3.74"

The month with the highest snowfall is December (3.74").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Grand Junction, CO

Average snowfall days in December - Grand Junction, CO
  • Average snowfall days in December: 6.9 days

The month with the highest number of snowfall days is January (7.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Grand Junction, CO

Average daylight in December / Average sunshine in December - Grand Junction, CO
  • Average daylight in December: 9h and 3min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in December: 6h and 4min

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

Average sunshine days in December
Grand Junction, CO

Average sunshine days in December - Grand Junction, CO
  • Average sunshine days in December: 19.5 days

The month with the most sunshine days is November (22.3 days).
The month with the least sunshine days is February (15.8 days).

Average UV index in December
Grand Junction, CO

Average UV index in December - Grand Junction, CO
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Grand Junction, CO

Average cloud cover in December - Grand Junction, CO
  • Average cloud cover in December: 28

The month with the most cloud cover is January (Cloud cover 31).
The months with the least cloud cover are June and September (Cloud cover 11).

Average visibility in December
Grand Junction, CO

Average visibility in December - Grand Junction, CO
  • Average visibility in December: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Grand Junction, Colorado, USA

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