December weather forecast
Thornton, CO

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Weather in December

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

Temperature

December, with an average high of 41.2°F (5.1°C) and a low of 21.9°F (-5.6°C), signifies the coldest month of the year.

Humidity

In December, the average relative humidity is 60%.

Rainfall

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

Snowfall

January through May, October through December are months with snowfall. In December, in Thornton, it is snowing for 2 days. Throughout December, 0.55" (14mm) of snow is accumulated. Throughout the year, there are 19.6 snowfall days, and 8.5" (216mm) 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 December, sunrise is at 7:02 am and sunset at 4:35 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:45 pm MST.

Sunshine

In Thornton, 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 reading of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, an average UV index of 2 transforms into the following instructions:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
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Frequently asked questions

What part of the year is the coldest in Thornton?

Thornton'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).

Is December cold in Thornton?

The high-temperature, in December, in Thornton, records 41.2°F (5.1°C), while the low-temperature is 21.9°F (-5.6°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, in July is appraised at 89.6°F (32°C).

What is the average humidity in December in Thornton?

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

What is the driest month in Thornton?

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 much does it rain in Thornton in December?

In Thornton, in December, during 1.7 rainfall days, 0.08" (2mm) of precipitation is typically accumulated.

How many days does it snow in December in Thornton?

In Thornton, Colorado, in December, during 2 snowfall days, 0.55" (14mm) of snow is typically accumulated.

What is the month with the shortest days in Thornton?

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

What is the average length of the day in December in Thornton?

The average day length in December in Thornton is 9h and 24min.

When is the sunrise / sunset in December in Thornton?

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, in Thornton, sunrise is at 7:21 am and sunset at 4:45 pm MST.

How long on average sun shines in December in Thornton?

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

What are the months with the lowest UV index in Thornton?

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

What is the UV index intensity in December in Thornton?

In December, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a minimal hazard to health 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
Thornton, CO

Average temperature in December - Thornton, 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).

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Average pressure in December
Thornton, CO

Average pressure in December - Thornton, 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).

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Average wind speed in December
Thornton, CO

Average wind speed in December - Thornton, 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).

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Average humidity in December
Thornton, CO

Average humidity in December - Thornton, 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%).

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Average rainfall in December
Thornton, CO

Average rainfall in December - Thornton, 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").

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Average rainfall days in December
Thornton, CO

Average rainfall days in December - Thornton, 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).

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Average snowfall in December
Thornton, CO

Average snowfall in December - Thornton, 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").

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Average snowfall days in December
Thornton, CO

Average snowfall days in December - Thornton, 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).

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

Average daylight in December / Average sunshine in December - Thornton, 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).

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Average sunshine days in December
Thornton, CO

Average sunshine days in December - Thornton, 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).

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Average UV index in December
Thornton, CO

Average UV index in December - Thornton, 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).

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Average cloud cover in December
Thornton, CO

Average cloud cover in December - Thornton, 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).

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Average visibility in December
Thornton, CO

Average visibility in December - Thornton, 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).

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Thornton, Colorado, USA

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