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
Arrival of December comes with a reduction in the average high-temperature, falling from a chilly 47.5°F (8.6°C) in November to an icy 35.8°F (2.1°C). An average nighttime temperature of 25°F (-3.9°C) is observed during December.Humidity
In December, the average relative humidity in Castleton, Illinois, is 81%.Rainfall
In December, the rain falls for 5.4 days. Throughout December, 0.63" (16mm) of precipitation is accumulated. In Castleton, during the entire year, the rain falls for 116.8 days and collects up to 13.98" (355mm) of precipitation.Snowfall
Months with snowfall in Castleton are January through April, October through December. In December, it is snowing for 5.8 days. Throughout December, 0.83" (21mm) of snow is accumulated. Throughout the year, in Castleton, there are 26.8 snowfall days, and 6.26" (159mm) of snow is accumulated.Daylight
December has the shortest days of the year in Castleton, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 7:05 am and sunset at 4:30 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 4:40 pm CST.
Sunshine
In Castleton, the average sunshine in December is 4.3h.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 rays for average individuals.Note: A maximum UV index of 1 in December translates into the following recommendations:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
Frequently asked questions
How cold is it in Castleton in December?
What is the average humidity in December in Castleton?
How much does it rain in Castleton in December?
How much does it snow in Castleton in December?
What is the month with the shortest days in Castleton?
What is the average length of the day in December in Castleton?
When is the sunrise / sunset in December in Castleton?
How many hours of sunshine does Castleton have in December?
When is the lowest UV index in Castleton?
What is the UV index intensity in December in Castleton?
Average temperature in December
Castleton, IL
- Average high temperature in December: 35.8°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in December: 25°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (17.8°F).
Average pressure in December
Castleton, IL
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Castleton, IL
- Average wind speed in December: 9.9mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).
Average humidity in December
Castleton, IL
- Average humidity in December: 81%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Castleton, IL
- Average rainfall in December: 0.63"
The wettest month (with the highest rainfall) is May (2.24").
The driest month (with the least rainfall) is January (0.59").
Average rainfall days in December
Castleton, IL
- Average rainfall days in December: 5.4 days
The month with the highest number of rainy days is May (15.2 days).
The months with the least rainy days are January and February (4.2 days).
Average snowfall in December
Castleton, IL
- Average snowfall in December: 0.83"
The month with the highest snowfall is January (1.81").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Castleton, IL
- Average snowfall days in December: 5.8 days
The month with the highest number of snowfall days is January (8.6 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
Castleton, IL
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 4h and 2min
The months with the most sunshine are June and July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Castleton, IL
- Average sunshine days in December: 20.4 days
The month with the most sunshine days is November (21.3 days).
The month with the least sunshine days is May (12.8 days).
Average UV index in December
Castleton, IL
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Castleton, IL
- Average cloud cover in December: 54
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in December
Castleton, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Castleton, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location
