December weather forecast
Jefferson, CO

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Weather in December

The first month of the winter, December, is also a subzero cold month in Jefferson, Colorado, with temperature in the range of an average low of 0.7°F (-17.4°C) and an average high of 21.2°F (-6°C).

Temperature

The coldest period tends to be December, when average temperatures fluctuate between a high of 21.2°F (-6°C) and a low of 0.7°F (-17.4°C).

Humidity

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

Rainfall

In December, the rain falls for 4.5 days. Throughout December, 1.34" (34mm) of precipitation is accumulated. Throughout the year, in Jefferson, there are 110.4 rainfall days, and 24.09" (612mm) of precipitation is accumulated.

Snowfall

January through December are months with snowfall. In Jefferson, in December, during 17.6 snowfall days, 10.83" (275mm) of snow is typically accumulated. In Jefferson, during the entire year, snow falls for 158 days and aggregates up to 118.82" (3018mm) of snow.

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 7:04 am and sunset at 4:40 pm. On the last day of December, in Jefferson, sunrise is at 7:23 am and sunset at 4:50 pm MST.

Sunshine

In Jefferson, the average sunshine in December is 5.5h.

UV index

The months with the lowest UV index are February and December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low threat to health from unsafe exposure to UV radiation for the average person.
Note: The maximum daily UV index of 1 in December converts into the following recommendations:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. To protect against the Sun's most potent rays, avoid direct exposure around midday. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Updated: Jul 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the coldest?

Jefferson's coldest weather arrives in December, when temperatures average a high of 21.2°F (-6°C) and a low of 0.7°F (-17.4°C).

How cold is December?

The high-temperature, in December, in Jefferson, records 21.2°F (-6°C), while the low-temperature is 0.7°F (-17.4°C).

What is the average humidity in December?

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

How much does it rain in December?

In December, in Jefferson, the rain falls for 4.5 days. Throughout December, 1.34" (34mm) of precipitation is accumulated.

How many days does it snow in December?

In December, in Jefferson, it is snowing for 17.6 days. Throughout December, 10.83" (275mm) of snow is accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 24min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 27min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:50 pm MST.

How long on average sun shines in December?

In December, the average sunshine duration is 5.5h.

What is the month with the lowest UV index in Jefferson?

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

What is the UV index intensity in December?

In December, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a low health threat 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
Jefferson, CO

Average temperature in December - Jefferson, CO
  • Average high temperature in December: 21.2°F

The warmest month (with the highest average high temperature) is July (65.8°F).
The month with the lowest average high temperature is December (21.2°F).

  • Average low temperature in December: 0.7°F

The month with the highest average low temperature is July (40.1°F).
The coldest months (with the lowest average low temperature) are January and December (0.7°F).

Average pressure in December
Jefferson, CO

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

The month with the highest atmospheric pressure is January (30.19"Hg).
The months with the lowest atmospheric pressure are April and May (29.94"Hg).

Average wind speed in December
Jefferson, CO

Average wind speed in December - Jefferson, 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 (4.8mph).

Average humidity in December
Jefferson, CO

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

The month with the highest relative humidity is February (89%).
The month with the lowest relative humidity is June (54%).

Average rainfall in December
Jefferson, CO

Average rainfall in December - Jefferson, CO
  • Average rainfall in December: 1.34"

The wettest month (with the highest rainfall) is July (3.35").
The driest month (with the least rainfall) is November (1.14").

Average rainfall days in December
Jefferson, CO

Average rainfall days in December - Jefferson, CO
  • Average rainfall days in December: 4.5 days

The month with the highest number of rainy days is July (22.8 days).
The month with the least rainy days is November (2.8 days).

Average snowfall in December
Jefferson, CO

Average snowfall in December - Jefferson, CO
  • Average snowfall in December: 10.83"

The month with the highest snowfall is May (19.69").
The month with the least snowfall is July (0.24").

Average snowfall days in December
Jefferson, CO

Average snowfall days in December - Jefferson, CO
  • Average snowfall days in December: 17.6 days

The month with the highest number of snowfall days is April (22.8 days).
The month with the least snowfall days is July (1.3 days).

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

Average daylight in December / Average sunshine in December - Jefferson, 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 3min

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 12min).

Average sunshine days in December
Jefferson, CO

Average sunshine days in December - Jefferson, CO
  • Average sunshine days in December: 13.2 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is July (5.8 days).

Average UV index in December
Jefferson, CO

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

The months with the highest UV index are May, June, July and August (UV index 3).
The months with the lowest UV index are February and December (UV index 1).

Average cloud cover in December
Jefferson, CO

Average cloud cover in December - Jefferson, CO
  • Average cloud cover in December: 48

The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is June (Cloud cover 19).

Average visibility in December
Jefferson, CO

Average visibility in December - Jefferson, 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).

Jefferson, Colorado, USA

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