December weather forecast
Derby, CO

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Weather in December

The first month of the winter, December, is also a wintry month in Derby, Colorado, with an average temperature varying between 21.9°F (-5.6°C) and 41.2°F (5.1°C).

Temperature

Derby's coldest month, December, registers temperatures that range from a high of 41.2°F (5.1°C) to a low of 21.9°F (-5.6°C).

Humidity

In Derby, the average relative humidity in December is 60%.

Rainfall

January and December are months with the least rain when the rain falls for 1.7 days and typically aggregates up to 0.08" (2mm) of rain.

Snowfall

Months with snowfall are January through May, October through December. In Derby, in December, snow falls for 2 days, with typically accumulated 0.55" (14mm) of snow. In Derby, during the entire year, snow falls for 19.6 days and aggregates up to 8.5" (216mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:02 am and sunset at 4:35 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:45 pm MST.

Sunshine

The average sunshine in December is 7h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to UV radiation for average individuals.
Note: The maximum UV index of 2 during December leads to these instructions:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Updated: Jul 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

Derby's December weather reaches an average high of 41.2°F (5.1°C) and an average low of 21.9°F (-5.6°C), making it the coldest month.

How cold does it get in December?

In December, the average high-temperature and low-temperature are 41.2°F (5.1°C) and 21.9°F (-5.6°C) respectively. In July, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines air temperature and relative humidity, is evaluated at 89.6°F (32°C).

What is the average humidity in December?

In Derby, the average relative humidity in December is 60%.

What is the driest month?

January and December are months with the least rain when the rain falls for 1.7 days and typically aggregates up to 0.08" (2mm) of rain.

How many days does it rain in December?

In December, the rain falls for 1.7 days. Throughout December, 0.08" (2mm) of precipitation is accumulated.

How much does it snow in December?

In December, it is snowing for 2 days. Throughout December, 0.55" (14mm) 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.

How many hours of daylight does Derby have in December?

In Derby, the average day length in December is 9h and 24min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:02 am and sunset at 4:35 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:45 pm MST.

How many hours of sunshine does Derby have in December?

In Derby, the average sunshine duration in December is 7h.

What is the month with the lowest UV index?

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

How high is the UV index in December?

The average daily maximum UV index in December is 2. 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
Derby, CO

Average temperature in December - Derby, CO
  • Average high temperature in December: 41.2°F

The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (41.2°F).

  • Average low temperature in December: 21.9°F

The month with the highest average low temperature is July (61.7°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).

Average pressure in December
Derby, CO

Average pressure in December - Derby, CO
  • Average pressure in December: 30.12"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are April and June (29.91"Hg).

Average wind speed in December
Derby, CO

Average wind speed in December - Derby, CO
  • Average wind speed in December: 5.8mph

The windiest month (with the highest average wind speed) is April (6.9mph).
The calmest month (with the lowest average wind speed) is December (5.8mph).

Average humidity in December
Derby, CO

Average humidity in December - Derby, CO
  • Average humidity in December: 60%

The month with the highest relative humidity is February (64%).
The month with the lowest relative humidity is August (39%).

Average rainfall in December
Derby, CO

Average rainfall in December - Derby, CO
  • Average rainfall in December: 0.08"

The wettest month (with the highest rainfall) is July (0.59").
The driest months (with the least rainfall) are January and December (0.08").

Average rainfall days in December
Derby, CO

Average rainfall days in December - Derby, CO
  • Average rainfall days in December: 1.7 days

The month with the highest number of rainy days is July (8.2 days).
The month with the least rainy days is February (1.2 days).

Average snowfall in December
Derby, CO

Average snowfall in December - Derby, CO
  • Average snowfall in December: 0.55"

The month with the highest snowfall is October (1.42").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Derby, CO

Average snowfall days in December - Derby, CO
  • Average snowfall days in December: 2 days

The month with the highest number of snowfall days is February (4.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in December: 7h and 0min

The months with the most sunshine are June and July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 42min).

Average sunshine days in December
Derby, CO

Average sunshine days in December - Derby, CO
  • Average sunshine days in December: 28.5 days

The month with the most sunshine days is December (28.5 days).
The month with the least sunshine days is July (19.6 days).

Average UV index in December
Derby, CO

Average UV index in December - Derby, 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
Derby, CO

Average cloud cover in December - Derby, CO
  • Average cloud cover in December: 22

The months with the most cloud cover are February, April and May (Cloud cover 25).
The month with the least cloud cover is September (Cloud cover 14).

Average visibility in December
Derby, CO

Average visibility in December - Derby, CO
  • 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).

Derby, Colorado, USA

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