December weather forecast
Riverton, IA

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Weather in December

December, the first month of the winter in Riverton, is also a wintry month, with an average temperature fluctuating between 23°F (-5°C) and 35.2°F (1.8°C).

Temperature

During the transition into December, Riverton observes a decrease in the average high-temperature, falling from a chilly 49.3°F (9.6°C) in November to a cold 35.2°F (1.8°C). Riverton encounters an average low-temperature of 23°F (-5°C) during December nights.

Humidity

The average relative humidity in December in Riverton is 77%.

Rainfall

In Riverton, during December, the rain falls for 5.1 days and regularly aggregates up to 1.26" (32mm) of precipitation. In Riverton, Iowa, during the entire year, the rain falls for 125.6 days and collects up to 26.14" (664mm) of precipitation.

Snowfall

Months with snowfall in Riverton, Iowa, are January through April, October through December. In Riverton, during December, snow falls for 5.6 days and regularly aggregates up to 1.85" (47mm) of snow. Throughout the year, in Riverton, there are 29.3 snowfall days, and 10.71" (272mm) of snow is accumulated.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:27 am and sunset at 4:55 pm. On the last day of December, in Riverton, sunrise is at 7:46 am and sunset at 5:05 pm CST.

Sunshine

The average sunshine in December is 5.1h.

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 low health risk from unsafe exposure to UV radiation for the ordinary person.
Note: A maximum daily UV index of 2 during December morphs into the following directions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in Riverton in December?

The average high-temperature and low-temperature during December are 35.2°F (1.8°C) and 23°F (-5°C) respectively. In August, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 89.6°F (32°C).

What is the average humidity in December in Riverton?

In Riverton, the average relative humidity in December is 77%.

How many days does it rain in December in Riverton?

In Riverton, during December, the rain falls for 5.1 days and regularly aggregates up to 1.26" (32mm) of precipitation.

How many days does it snow in December in Riverton?

In Riverton, in December, during 5.6 snowfall days, 1.85" (47mm) of snow is typically accumulated.

What is the month with the shortest days in Riverton?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

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

In December, the average day length in Riverton, Iowa, is 9h and 19min.

When is the sunrise / sunset in December in Riverton?

On the first day of December in Riverton, Iowa, sunrise is at 7:27 am and sunset at 4:55 pm. On the last day of the month, sunrise is at 7:46 am and sunset at 5:05 pm CST.

How many hours of sunshine does Riverton have in December?

The average sunshine duration in December in Riverton, Iowa, is 5.1h.

When is the lowest UV index in Riverton?

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

How high is the UV index in December in Riverton?

The average daily maximum UV index in December in Riverton is 2. A UV Index value of 2, and less, symbolizes 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
Riverton, IA

Average temperature in December - Riverton, IA
  • Average high temperature in December: 35.2°F

The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (31.3°F).

  • Average low temperature in December: 23°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (18°F).

Average pressure in December
Riverton, IA

Average pressure in December - Riverton, IA
  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in December
Riverton, IA

Average wind speed in December - Riverton, IA
  • Average wind speed in December: 9.4mph

The windiest month (with the highest average wind speed) is April (10.3mph).
The calmest month (with the lowest average wind speed) is July (6.7mph).

Average humidity in December
Riverton, IA

Average humidity in December - Riverton, IA
  • Average humidity in December: 77%

The months with the highest relative humidity are January and July (79%).
The month with the lowest relative humidity is October (67%).

Average rainfall in December
Riverton, IA

Average rainfall in December - Riverton, IA
  • Average rainfall in December: 1.26"

The wettest month (with the highest rainfall) is June (4.29").
The driest month (with the least rainfall) is February (0.71").

Average rainfall days in December
Riverton, IA

Average rainfall days in December - Riverton, IA
  • Average rainfall days in December: 5.1 days

The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is February (3.9 days).

Average snowfall in December
Riverton, IA

Average snowfall in December - Riverton, IA
  • Average snowfall in December: 1.85"

The month with the highest snowfall is January (3.11").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Riverton, IA

Average snowfall days in December - Riverton, IA
  • Average snowfall days in December: 5.6 days

The month with the highest number of snowfall days is January (8.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Riverton, IA
  • 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 18min).

  • Average sunshine in December: 5h and 1min

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

Average sunshine days in December
Riverton, IA

Average sunshine days in December - Riverton, IA
  • Average sunshine days in December: 20.6 days

The month with the most sunshine days is November (20.8 days).
The month with the least sunshine days is June (11.8 days).

Average UV index in December
Riverton, IA

Average UV index in December - Riverton, IA
  • 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
Riverton, IA

Average cloud cover in December - Riverton, IA
  • Average cloud cover in December: 44

The month with the most cloud cover is January (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 26).

Average visibility in December
Riverton, IA

Average visibility in December - Riverton, IA
  • 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).

Riverton, Iowa, USA

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