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
December's arrival comes with a decrease in the average high-temperature, moving from a chilly 44.8°F (7.1°C) in November to an icy 32.5°F (0.3°C). An average low-temperature of 22.3°F (-5.4°C) is noted during the month of December.Humidity
The average relative humidity in December is 83%.Rainfall
In Shannon, in December, during 5.9 rainfall days, 0.87" (22mm) of precipitation is typically accumulated. Throughout the year, there are 130.8 rainfall days, and 17.95" (456mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Shannon, during December, snow falls for 8.6 days and regularly aggregates up to 1.42" (36mm) of snow. In Shannon, during the entire year, snow falls for 39.2 days and aggregates up to 8.62" (219mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:08 am and sunset at 4:27 pm. On the last day of December, sunrise is at 7:27 am and sunset at 4:37 pm CST.
Sunshine
In Shannon, the average sunshine in December is 4h.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for average individuals.Note: In December, a daily maximum UV index of 1 leads to the following instructions:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.
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 Shannon have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Shannon have in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Shannon, IL
- Average high temperature in December: 32.5°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 (25.9°F).
- Average low temperature in December: 22.3°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in December
Shannon, IL
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Shannon, IL
- Average wind speed in December: 9.4mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in December
Shannon, IL
- Average humidity in December: 83%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in December
Shannon, IL
- Average rainfall in December: 0.87"
The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").
Average rainfall days in December
Shannon, IL
- Average rainfall days in December: 5.9 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in December
Shannon, IL
- Average snowfall in December: 1.42"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Shannon, IL
- Average snowfall days in December: 8.6 days
The month with the highest number of snowfall days is January (11.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Shannon, IL
- 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 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Shannon, IL
- Average sunshine days in December: 18.4 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).
Average UV index in December
Shannon, IL
- Average UV index in December: 1
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Shannon, IL
- Average cloud cover in December: 58
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in December
Shannon, IL
- 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).
Shannon, Illinois, USA
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