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 change in temperatures is noted as November gives way to December, with average highs reducing from a chilly 45.3°F (7.4°C) to a wintry 33.1°F (0.6°C). An average low-temperature of 23°F (-5°C) is noted during the month of December.Humidity
In DeKalb, the average relative humidity in December is 83%.Rainfall
In DeKalb, in December, it is raining for 8.5 days, with typically 1.69" (43mm) of accumulated precipitation. In DeKalb, during the entire year, the rain falls for 152.6 days and collects up to 32.09" (815mm) of precipitation.Snowfall
Months with snowfall are January through May, October through December. In DeKalb, in December, snow falls for 10 days, with typically accumulated 2.91" (74mm) of snow. In DeKalb, during the entire year, snow falls for 44.3 days and aggregates up to 17.87" (454mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 7:03 am and sunset at 4:24 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:33 pm CST.
Sunshine
In December, the average sunshine is 3.9h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for average individuals.Note: The maximum daily UV index of 1 in December converts into the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Beware! Reflection from snow can magnify the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December in DeKalb?
How much does it rain in December?
How many days does it snow in December?
What is the month with the shortest days in DeKalb?
How many hours of daylight does DeKalb have in December?
What time are sunrise and sunset in December?
How many hours of sunshine does DeKalb have in December?
What are the months with the lowest UV index?
How high is the UV index in December?
Average temperature in December
DeKalb, IL
- Average high temperature in December: 33.1°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in December: 23°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in December
DeKalb, IL
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
DeKalb, IL
- Average wind speed in December: 9.3mph
The windiest month (with the highest average wind speed) is April (10mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).
Average humidity in December
DeKalb, IL
- Average humidity in December: 83%
The months with the highest relative humidity are January and July (85%).
The months with the lowest relative humidity are April and October (75%).
Average rainfall in December
DeKalb, IL
- Average rainfall in December: 1.69"
The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.65").
Average rainfall days in December
DeKalb, IL
- Average rainfall days in December: 8.5 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (4.7 days).
Average snowfall in December
DeKalb, IL
- Average snowfall in December: 2.91"
The month with the highest snowfall is January (5.55").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
DeKalb, IL
- Average snowfall days in December: 10 days
The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
DeKalb, 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: 3h and 5min
The month with the most sunshine is July (Average sunshine: 9h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
DeKalb, IL
- Average sunshine days in December: 15.5 days
The month with the most sunshine days is November (17.2 days).
The months with the least sunshine days are June and July (10.3 days).
Average UV index in December
DeKalb, IL
- Average UV index in December: 1
The months with the highest UV index are June and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
DeKalb, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are August and September (Cloud cover 35).
Average visibility in December
DeKalb, IL
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, February, July, August and September (5mi).
DeKalb, Illinois, USA
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