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
Williamson's transition into December involves a shift in temperature, receding from a fresh 51.6°F (10.9°C) in November to an icy 40.3°F (4.6°C). Williamson sees an average low-temperature of 29.1°F (-1.6°C) during December.Humidity
In December, the average relative humidity is 78%.Rainfall
In Williamson, Illinois, in December, it is raining for 6.7 days, with typically 0.87" (22mm) of accumulated precipitation. Throughout the year, in Williamson, Illinois, there are 121.4 rainfall days, and 14.72" (374mm) of precipitation is accumulated.Snowfall
January through March, November and December are months with snowfall in Williamson. The month with the most snowfall in Williamson is December, when snow falls for 3.8 days and typically aggregates up to 0.98" (25mm) of snow.Daylight
December has the shortest days of the year in Williamson, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 6:59 am and sunset at 4:37 pm. On the last day of December, sunrise is at 7:17 am and sunset at 4:47 pm CST.
Sunshine
In December, the average sunshine in Williamson is 4.8h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Williamson. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV rays for average individuals.Note: In December, the UV index of 2 transforms into the following advice:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Frequently asked questions
How cold does it get in Williamson in December?
What is the average humidity in December in Williamson?
How many days does it rain in December in Williamson?
What is the snowiest month in Williamson?
How much does it snow in Williamson in December?
What is the month with the shortest days in Williamson?
What is the average length of the day in December in Williamson?
When are sunrise and sunset in December in Williamson?
How many hours of sunshine does Williamson have in December?
What is the month with the lowest UV index in Williamson?
How high is the UV index in December in Williamson?
Average temperature in December
Williamson, IL
- Average high temperature in December: 40.3°F
The warmest month (with the highest average high temperature) is July (84.2°F).
The month with the lowest average high temperature is January (35.6°F).
- Average low temperature in December: 29.1°F
The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in December
Williamson, IL
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Williamson, IL
- Average wind speed in December: 9.3mph
The windiest month (with the highest average wind speed) is January (10mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).
Average humidity in December
Williamson, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Williamson, IL
- Average rainfall in December: 0.87"
The wettest month (with the highest rainfall) is June (1.89").
The driest month (with the least rainfall) is February (0.67").
Average rainfall days in December
Williamson, IL
- Average rainfall days in December: 6.7 days
The month with the highest number of rainy days is July (14 days).
The month with the least rainy days is January (5.8 days).
Average snowfall in December
Williamson, IL
- Average snowfall in December: 0.98"
The month with the highest snowfall is December (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Williamson, IL
- Average snowfall days in December: 3.8 days
The month with the highest number of snowfall days is January (6.3 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
Williamson, 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 5min
The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in December
Williamson, IL
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is January (20.9 days).
The month with the least sunshine days is July (12.5 days).
Average UV index in December
Williamson, IL
- 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
Williamson, IL
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are June, July, August and September (Cloud cover 29).
Average visibility in December
Williamson, IL
- 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).
Williamson, Illinois, USA
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