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
During the transition into December, Grayslake observes a decrease in the average high-temperature, falling from a frosty 45.1°F (7.3°C) in November to a cold 33.6°F (0.9°C). Grayslake experiences an average nighttime temperature of 23.9°F (-4.5°C) in the month of December.Humidity
The average relative humidity in December is 81%.Rainfall
December is the month with the least rainfall. Rain falls for 8.2 days and accumulates 0.98" (25mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Grayslake, Illinois, in December, during 10.4 snowfall days, 2.17" (55mm) of snow is typically accumulated. Throughout the year, in Grayslake, there are 49.5 snowfall days, and 13.54" (344mm) of snow is accumulated.Daylight
The month with the shortest days in Grayslake is December, with an average of 9h and 6min of daylight.On the first day of December, sunrise is at 7:02 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:29 pm CST.
Sunshine
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 low health risk from exposure to the Sun's UV radiation for the average person.Note: In December, the maximum UV index of 1 suggests these recommendations:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. The solar radiation around mid-day is intense; avoid the Sun and stay safe. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
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?
What is the driest month?
How much does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Grayslake have in December?
What are the months with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Grayslake, IL
- Average high temperature in December: 33.6°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 (27.5°F).
- Average low temperature in December: 23.9°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (16.5°F).
Average pressure in December
Grayslake, IL
- Average pressure in December: 30.09"Hg
The months with the highest atmospheric pressure are January and February (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Grayslake, IL
- Average wind speed in December: 9.6mph
The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in December
Grayslake, IL
- Average humidity in December: 81%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (74%).
Average rainfall in December
Grayslake, IL
- Average rainfall in December: 0.98"
The wettest month (with the highest rainfall) is April (2.72").
The driest month (with the least rainfall) is December (0.98").
Average rainfall days in December
Grayslake, IL
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is July (17.5 days).
The month with the least rainy days is February (5 days).
Average snowfall in December
Grayslake, IL
- Average snowfall in December: 2.17"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Grayslake, IL
- Average snowfall days in December: 10.4 days
The month with the highest number of snowfall days is January (13.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Grayslake, 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 6min).
- Average sunshine in December: 4h and 0min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Grayslake, IL
- Average sunshine days in December: 15.4 days
The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is May (10.8 days).
Average UV index in December
Grayslake, IL
- Average UV index in December: 1
The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Grayslake, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are July, August and September (Cloud cover 30).
Average visibility in December
Grayslake, IL
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Grayslake, Illinois, USA
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