December weather forecast
Thornton, IA

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Weather in December

December, the first month of the winter in Thornton, is still a freezing cold month, with an average temperature ranging between max 28.8°F (-1.8°C) and min 18.3°F (-7.6°C).

Temperature

Thornton's December weather is marked by a distinct drop in high-temperatures, declining from a chilly 43.2°F (6.2°C) in November to a subzero cold 28.8°F (-1.8°C). Thornton, in December, observes a steady average low-temperature of 18.3°F (-7.6°C).

Humidity

The average relative humidity in December in Thornton is 84%.

Rainfall

In Thornton, Iowa, during December, the rain falls for 4.6 days and regularly aggregates up to 1.42" (36mm) of precipitation. In Thornton, during the entire year, the rain falls for 136.3 days and collects up to 26.18" (665mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. In Thornton, in December, snow falls for 9.7 days, with typically accumulated 2.87" (73mm) of snow. Throughout the year, there are 44.7 snowfall days, and 20.51" (521mm) of snow is accumulated.

Daylight

December has the shortest days of the year in Thornton, with an average of 9h and 6min of daylight.
On the first day of the month, sunrise is at 7:25 am and sunset at 4:40 pm. On the last day of December, sunrise is at 7:44 am and sunset at 4:49 pm CST.

Sunshine

In Thornton, the average sunshine in December is 4.2h.

UV index

January through March, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Thornton. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: In December, the maximum UV index of 2 suggests this advice:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Boost your sun resistance with garments that are densely woven yet spacious. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December in Thornton?

The average high-temperature, in December, in Thornton, is 28.8°F (-1.8°C), while the average low-temperature is 18.3°F (-7.6°C).

What is the average humidity in December in Thornton?

In Thornton, Iowa, the average relative humidity in December is 84%.

How many days does it rain in December in Thornton?

In Thornton, Iowa, during December, the rain falls for 4.6 days and regularly aggregates up to 1.42" (36mm) of precipitation.

How many days does it snow in December in Thornton?

In Thornton, during December, snow falls for 9.7 days and regularly aggregates up to 2.87" (73mm) of snow.

What is the month with the shortest days in Thornton?

The month with the shortest days in Thornton, Iowa, is December, with an average of 9h and 6min of daylight.

How many hours of daylight does Thornton have in December?

In Thornton, the average day length in December is 9h and 5min.

What time are sunrise and sunset in December in Thornton?

In December, on the first day of the month, sunrise is at 7:25 am and sunset at 4:40 pm. On the last day of the month, sunrise is at 7:44 am and sunset at 4:49 pm CST.

How many hours of sunshine does Thornton have in December?

In December, the average sunshine duration in Thornton is 4.2h.

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

The months with the lowest UV index in Thornton are January through March, October through December, with an average maximum UV index of 2.

How high is the UV index in December in Thornton?

The average daily maximum UV index in December in Thornton, Iowa, is 2. A UV Index of 2, and less, symbolizes a low health threat from exposure to the Sun's 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
Thornton, IA

Average temperature in December - Thornton, IA
  • Average high temperature in December: 28.8°F

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (23.4°F).

  • Average low temperature in December: 18.3°F

The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (10.8°F).

Average pressure in December
Thornton, IA

Average pressure in December - Thornton, IA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

Average wind speed in December
Thornton, IA

Average wind speed in December - Thornton, IA
  • Average wind speed in December: 10.5mph

The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.3mph).

Average humidity in December
Thornton, IA

Average humidity in December - Thornton, IA
  • Average humidity in December: 84%

The month with the highest relative humidity is January (88%).
The month with the lowest relative humidity is October (70%).

Average rainfall in December
Thornton, IA

Average rainfall in December - Thornton, IA
  • Average rainfall in December: 1.42"

The wettest month (with the highest rainfall) is June (3.98").
The driest month (with the least rainfall) is January (0.98").

Average rainfall days in December
Thornton, IA

Average rainfall days in December - Thornton, IA
  • Average rainfall days in December: 4.6 days

The month with the highest number of rainy days is June (18.6 days).
The month with the least rainy days is February (2.8 days).

Average snowfall in December
Thornton, IA

Average snowfall in December - Thornton, IA
  • Average snowfall in December: 2.87"

The month with the highest snowfall is February (5.94").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Thornton, IA

Average snowfall days in December - Thornton, IA
  • Average snowfall days in December: 9.7 days

The month with the highest number of snowfall days is January (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Thornton, IA
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in December: 4h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in December
Thornton, IA

Average sunshine days in December - Thornton, IA
  • Average sunshine days in December: 17.8 days

The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is June (10 days).

Average UV index in December
Thornton, IA

Average UV index in December - Thornton, IA
  • Average UV index in December: 2

The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in December
Thornton, IA

Average cloud cover in December - Thornton, IA
  • Average cloud cover in December: 57

The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are August and September (Cloud cover 32).

Average visibility in December
Thornton, IA

Average visibility in December - Thornton, IA
  • Average visibility in December: 6mi

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

Thornton, Iowa, USA

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