December weather forecastClayton, IL
December
Weather in December
The first month of the winter, December, is still a cold month in Clayton, Illinois, with an average temperature ranging between max 38.5°F (3.6°C) and min 26.8°F (-2.9°C).Temperature
The start of December signals a decrease in the average high-temperature, transitioning from a cool 50°F (10°C) in November to a cold 38.5°F (3.6°C). Throughout the month of December, the average temperature dips to a freezing cold 26.8°F (-2.9°C) at night.Humidity
In Clayton, the average relative humidity in December is 78%.Rainfall
In Clayton, in December, during 6.4 rainfall days, 1.06" (27mm) of precipitation is typically accumulated. Throughout the year, there are 132 rainfall days, and 22.17" (563mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. In Clayton, in December, snow falls for 4.7 days, with typically accumulated 1.18" (30mm) of snow. Throughout the year, there are 23.8 snowfall days, and 8.5" (216mm) of snow is accumulated.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:07 am and sunset at 4:39 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 4:48 pm CST.
Sunshine
In Clayton, the average sunshine in December is 4.6h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The UV index of 2 in December translates into these instructions:
While most people can stay under the sun for an hour without burning, children must always be guarded against sun exposure. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Clayton, IL
- Average high temperature in December: 38.5°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (32.7°F).
- Average low temperature in December: 26.8°F
The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (20.3°F).
Average pressure in December
Clayton, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Clayton, IL
- Average wind speed in December: 9.7mph
The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is July (6.3mph).
Average humidity in December
Clayton, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Clayton, IL
- Average rainfall in December: 1.06"
The wettest month (with the highest rainfall) is May (3.23").
The driest month (with the least rainfall) is January (0.98").
Average rainfall days in December
Clayton, IL
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is May (16.9 days).
The months with the least rainy days are January and February (5.3 days).
Average snowfall in December
Clayton, IL
- Average snowfall in December: 1.18"
The month with the highest snowfall is January (3.19").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Clayton, IL
- Average snowfall days in December: 4.7 days
The month with the highest number of snowfall days is January (7.8 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
Clayton, IL
- Average daylight in December: 9h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 4h and 36min
The months with the most sunshine are June and July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in December
Clayton, IL
- Average sunshine days in December: 19.4 days
The month with the most sunshine days is January (20 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in December
Clayton, 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
Clayton, IL
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July, August and September (Cloud cover 30).
Average visibility in December
Clayton, 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).
