Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The onset of December comes with a shift in the average high-temperature, falling from a frosty 44.4°F (6.9°C) in November to a freezing cold 30.9°F (-0.6°C). Throughout December, Union's nights cool down to an average of 20.1°F (-6.6°C).Humidity
The average relative humidity in December is 82%.Rainfall
In Union, Iowa, in December, it is raining for 3 days, with typically 0.28" (7mm) of accumulated precipitation. In Union, during the entire year, the rain falls for 83.5 days and collects up to 6.5" (165mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Union, Iowa, in December, snow falls for 4.9 days, with typically accumulated 0.43" (11mm) of snow. In Union, during the entire year, snow falls for 26.6 days and aggregates up to 3.03" (77mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year in Union.On the first day of the month, sunrise is at 7:22 am and sunset at 4:40 pm. On the last day of December, sunrise is at 7:40 am and sunset at 4:50 pm CST.
Sunshine
In Union, the average sunshine in December is 4.4h.UV index
January, February, October through 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 exposure to the Sun's UV radiation for the average person.Note: The average daily UV index of 2 in December transforms into the following instructions:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Experience reduced UV exposure by about half when donning a wide-brim hat. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When are sunrise and sunset in December?
How many hours of sunshine does Union have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Union, IA
- Average high temperature in December: 30.9°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (24.4°F).
- Average low temperature in December: 20.1°F
The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (12.2°F).
Average pressure in December
Union, 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 (29.89"Hg).
Average wind speed in December
Union, IA
- Average wind speed in December: 10.3mph
The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in December
Union, IA
- Average humidity in December: 82%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Union, IA
- Average rainfall in December: 0.28"
The wettest month (with the highest rainfall) is May (1.06").
The driest months (with the least rainfall) are January and February (0.24").
Average rainfall days in December
Union, IA
- Average rainfall days in December: 3 days
The month with the highest number of rainy days is May (11.6 days).
The months with the least rainy days are January and February (2 days).
Average snowfall in December
Union, IA
- Average snowfall in December: 0.43"
The month with the highest snowfall is February (0.79").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Union, IA
- Average snowfall days in December: 4.9 days
The month with the highest number of snowfall days is January (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
Union, IA
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 2min
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 54min).
Average sunshine days in December
Union, IA
- Average sunshine days in December: 24.6 days
The month with the most sunshine days is January (25.2 days).
The month with the least sunshine days is June (15.8 days).
Average UV index in December
Union, IA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in December
Union, IA
- Average cloud cover in December: 55
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 31).
Average visibility in December
Union, IA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Union, Iowa, USA
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