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
A decrease in the average high-temperature is observed during December, shifting from a fresh 50.5°F (10.3°C) in November to a wintry 39.7°F (4.3°C). Casey throughout December, records an average low-temperature of 28.9°F (-1.7°C).Humidity
In December, the average relative humidity is 80%.Rainfall
In Casey, during December, the rain falls for 6.5 days and regularly aggregates up to 0.79" (20mm) of precipitation. Throughout the year, there are 115.9 rainfall days, and 11.26" (286mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall. December is the month with the most snowfall. Snow falls for 4 days and accumulates 0.47" (12mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 6:53 am and sunset at 4:29 pm. On the last day of December, sunrise is at 7:11 am and sunset at 4:39 pm CST.
Sunshine
In December, the average sunshine in Casey is 4.4h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV rays for the average person.Note: The maximum daily UV index of 1 in December converts into the following recommendations:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold during December?
What is the average humidity in December?
How much does it rain in December?
When does it snow the most?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Casey have in December?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Casey, IL
- Average high temperature in December: 39.7°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (34.7°F).
- Average low temperature in December: 28.9°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in December
Casey, IL
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Casey, IL
- Average wind speed in December: 9.6mph
The windiest months (with the highest average wind speed) are January and February (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.1mph).
Average humidity in December
Casey, IL
- Average humidity in December: 80%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Casey, IL
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is April (1.54").
The driest month (with the least rainfall) is February (0.47").
Average rainfall days in December
Casey, IL
- Average rainfall days in December: 6.5 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (6 days).
Average snowfall in December
Casey, IL
- Average snowfall in December: 0.47"
The month with the highest snowfall is December (0.47").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Casey, IL
- Average snowfall days in December: 4 days
The month with the highest number of snowfall days is January (5.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Casey, IL
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Casey, IL
- Average sunshine days in December: 20.8 days
The month with the most sunshine days is October (21.2 days).
The month with the least sunshine days is May (12.4 days).
Average UV index in December
Casey, IL
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Casey, IL
- Average cloud cover in December: 53
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is June (Cloud cover 30).
Average visibility in December
Casey, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).
Casey, Illinois, USA
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