December weather forecast
Dillon, CO

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The brown and golden trees near the iconic Dillon reservoir in Colorado
The brown and golden trees near the iconic Dillon reservoir in Colorado

Weather in December

As the year concludes, December presents Dillon under a pristine snow blanket accumulating up to 9.49" (241mm). The festive spirit is in the air, and snow-covered landscapes create an enchanting aura. The winding down of the year is marked by cooler temperatures, plenty of snowfall, and a remarkable number of daylight hours. With the city beautifully lit up, it’s an ideal time for holiday-themed photographs. Despite the cold, Dillon concludes the calendar with a heartwarming ambiance.

Temperature

December, characterized by an average high temperature of 22.5°F (-5.3°C) and a low temperature of 0.9°F (-17.3°C), is generally the coldest month.

Humidity

In Dillon, the average relative humidity in December is 85%.

Rainfall

In Dillon, in December, it is raining for 4.3 days, with typically 1.18" (30mm) of accumulated precipitation. In Dillon, during the entire year, the rain falls for 111.5 days and collects up to 23.19" (589mm) of precipitation.

Snowfall

Months with snowfall are January through December. In Dillon, in December, during 16.7 snowfall days, 9.49" (241mm) of snow is typically accumulated. Throughout the year, there are 149 snowfall days, and 108.54" (2757mm) of snow is accumulated.

Daylight

With an average of 9h and 24min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:06 am and sunset at 4:40 pm. On the last day of December, sunrise is at 7:24 am and sunset at 4:50 pm MST.

Sunshine

The average sunshine in December is 5.6h.

UV index

February, November and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for average individuals.
Note: A maximum UV index of 1 in December translates into the following recommendations:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Updated: Jul 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

Dillon witnesses the coldest weather in December, with temperatures averaging a high of 22.5°F (-5.3°C) and a low of 0.9°F (-17.3°C).

How cold is it in December?

The average high-temperature and low-temperature during December are 22.5°F (-5.3°C) and 0.9°F (-17.3°C) respectively.

What is the average humidity in December?

In Dillon, the average relative humidity in December is 85%.

How much does it rain in December?

In Dillon, in December, it is raining for 4.3 days, with typically 1.18" (30mm) of accumulated precipitation.

How much does it snow in December?

In December, it is snowing for 16.7 days. Throughout December, 9.49" (241mm) of snow is accumulated.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 24min of daylight.

What is the average length of the day in December?

In Dillon, the average day length in December is 9h and 25min.

When are sunrise and sunset in December?

On the first day of December, sunrise is at 7:06 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 4:50 pm MST.

How long on average sun shines in December?

In December, the average sunshine duration is 5.6h.

When is the lowest UV index?

The months with the lowest UV index are February, November and December, with an average maximum UV index of 1.

What is the UV index reading in December?

In Dillon, the average daily maximum UV index in December is 1. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to 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
Dillon, CO

Average temperature in December - Dillon, CO
  • Average high temperature in December: 22.5°F

The warmest month (with the highest average high temperature) is July (67.1°F).
The month with the lowest average high temperature is December (22.5°F).

  • Average low temperature in December: 0.9°F

The month with the highest average low temperature is July (39.7°F).
The coldest month (with the lowest average low temperature) is December (0.9°F).

Average pressure in December
Dillon, CO

Average pressure in December - Dillon, CO
  • Average pressure in December: 30.16"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is April (29.93"Hg).

Average wind speed in December
Dillon, CO

Average wind speed in December - Dillon, CO
  • Average wind speed in December: 6.2mph

The windiest month (with the highest average wind speed) is February (7mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

Average humidity in December
Dillon, CO

Average humidity in December - Dillon, CO
  • Average humidity in December: 85%

The month with the highest relative humidity is February (88%).
The month with the lowest relative humidity is June (53%).

Average rainfall in December
Dillon, CO

Average rainfall in December - Dillon, CO
  • Average rainfall in December: 1.18"

The wettest month (with the highest rainfall) is July (3.39").
The driest month (with the least rainfall) is January (1.06").

Average rainfall days in December
Dillon, CO

Average rainfall days in December - Dillon, CO
  • Average rainfall days in December: 4.3 days

The month with the highest number of rainy days is July (22.7 days).
The month with the least rainy days is November (2.8 days).

Average snowfall in December
Dillon, CO

Average snowfall in December - Dillon, CO
  • Average snowfall in December: 9.49"

The month with the highest snowfall is April (18.27").
The month with the least snowfall is July (0.47").

Average snowfall days in December
Dillon, CO

Average snowfall days in December - Dillon, CO
  • Average snowfall days in December: 16.7 days

The month with the highest number of snowfall days is April (21 days).
The month with the least snowfall days is July (1.8 days).

Average daylight in December /
Average sunshine in December
Dillon, CO

Average daylight in December / Average sunshine in December - Dillon, CO
  • Average daylight in December: 9h and 2min

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 24min).

  • Average sunshine in December: 5h and 4min

The month with the most sunshine is June (Average sunshine: 11h and 24min).
The month with the least sunshine is February (Average sunshine: 5h and 24min).

Average sunshine days in December
Dillon, CO

Average sunshine days in December - Dillon, CO
  • Average sunshine days in December: 14.5 days

The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is July (5.3 days).

Average UV index in December
Dillon, CO

Average UV index in December - Dillon, CO
  • Average UV index in December: 1

The months with the highest UV index are July and August (UV index 4).
The months with the lowest UV index are February, November and December (UV index 1).

Average cloud cover in December
Dillon, CO

Average cloud cover in December - Dillon, CO
  • Average cloud cover in December: 47

The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is June (Cloud cover 19).

Average visibility in December
Dillon, CO

Average visibility in December - Dillon, CO
  • Average visibility in December: 4mi

The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April and December (4mi).

Dillon, Colorado, USA

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