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 brings a distinct decrease in the average high-temperature, receding from a chilly 43.2°F (6.2°C) in November to a freezing cold 27.5°F (-2.5°C). In December, Royal encounters an average low-temperature of 16.9°F (-8.4°C) during the night.Humidity
In Royal, the average relative humidity in December is 84%.Rainfall
In Royal, in December, it is raining for 4 days, with typically 0.83" (21mm) of accumulated precipitation. In Royal, during the entire year, the rain falls for 112.3 days and collects up to 15.31" (389mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Royal, during December, snow falls for 9.9 days and regularly aggregates up to 2.05" (52mm) of snow. Throughout the year, there are 45.5 snowfall days, and 11.14" (283mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 7:33 am and sunset at 4:47 pm. On the last day of December, sunrise is at 7:52 am and sunset at 4:56 pm CST.
Sunshine
In Royal, the average sunshine in December is 4.4h.UV index
The average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for the average person.Note: In December, a regular UV index of 2 translates into these guidelines:
While most people are not greatly affected by extended sun exposure, those with fair skin, babies, and children must always have protection. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
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?
How many hours of daylight does Royal have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Royal have in December?
What is the UV index intensity in December?
Average temperature in December
Royal, IA
- Average high temperature in December: 27.5°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (22.8°F).
- Average low temperature in December: 16.9°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 (10.6°F).
Average pressure in December
Royal, IA
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in December
Royal, IA
- Average wind speed in December: 10.7mph
The windiest months (with the highest average wind speed) are January and April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.6mph).
Average humidity in December
Royal, IA
- Average humidity in December: 84%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (68%).
Average rainfall in December
Royal, IA
- Average rainfall in December: 0.83"
The wettest month (with the highest rainfall) is June (2.44").
The driest month (with the least rainfall) is January (0.43").
Average rainfall days in December
Royal, IA
- Average rainfall days in December: 4 days
The month with the highest number of rainy days is May (15.5 days).
The month with the least rainy days is February (2.7 days).
Average snowfall in December
Royal, IA
- Average snowfall in December: 2.05"
The month with the highest snowfall is February (2.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Royal, IA
- Average snowfall days in December: 9.9 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
Royal, 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 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in December
Royal, IA
- Average sunshine days in December: 19.2 days
The month with the most sunshine days is November (20.1 days).
The month with the least sunshine days is June (10.8 days).
Average UV index in December
Royal, 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 and February (UV index 1).
Average cloud cover in December
Royal, 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 July (Cloud cover 30).
Average visibility in December
Royal, 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).
Royal, Iowa, USA
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