December weather forecastLake Bluff, IL
December
Weather in December
December in Lake Bluff announces the full blown winter season, witness the year's maximum snowfall of 2.05" (52mm). The transition into areas coated in flurries is gradual, echoing the shifting weather patterns over November. Lakes transform into icy plains, while Christmas decorations breathe life into white landscapes. Scarves flutter around as the chilly winds create an enchanting atmosphere. As December ensues, Lake Bluff gleams with excitement, marking the holiday season and the start of another cycle of weather patterns.Temperature
The shift from November to December corresponds with a decrease in the average high-temperature, down to an icy 34.5°F (1.4°C) from a chilly 45.5°F (7.5°C). December nights reflect a consistent temperature dip to a subzero cold 26.2°F (-3.2°C), a slight descent from daytime peaks.Humidity
In December, the average relative humidity is 80%.Rainfall
December is the month with the least rainfall. Rain falls for 8.6 days and accumulates 1.3" (33mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In December, it is snowing for 9.1 days. Throughout December, 2.05" (52mm) of snow is accumulated. Throughout the year, there are 42.9 snowfall days, and 13.82" (351mm) of snow is accumulated.Ocean temperature
In Lake Bluff, the average seawater temperature in December is 41.7°F (5.4°C).Note: In 41.7°F (5.4°C), even brief exposure to 55.4°F (13°C) feels biting, and anything less than 50°F (10°C) risks cold shock and impaired breathing, considering one's health.
Daylight
December has the shortest days of the year, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 7:01 am and sunset at 4:20 pm. On the last day of December, sunrise is at 7:20 am and sunset at 4:29 pm CST.
Sunshine
In Lake Bluff, Illinois, the average sunshine in December is 4.1h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: In December, the maximum UV index of 1 suggests this advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Lake Bluff, IL
- Average high temperature in December: 34.5°F
The warmest month (with the highest average high temperature) is July (77.7°F).
The month with the lowest average high temperature is January (28.6°F).
- Average low temperature in December: 26.2°F
The months with the highest average low temperature are July and August (66.7°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Lake Bluff, IL
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Lake Bluff, IL
- Average wind speed in December: 11.2mph
The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).
Average humidity in December
Lake Bluff, IL
- Average humidity in December: 80%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in December
Lake Bluff, IL
- Average rainfall in December: 1.3"
The wettest months (with the highest rainfall) are May and June (3.82").
The driest month (with the least rainfall) is December (1.3").
Average rainfall days in December
Lake Bluff, IL
- Average rainfall days in December: 8.6 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (5.9 days).
Average snowfall in December
Lake Bluff, IL
- Average snowfall in December: 2.05"
The month with the highest snowfall is January (4.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Lake Bluff, IL
- Average snowfall days in December: 9.1 days
The month with the highest number of snowfall days is January (11.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in December
Lake Bluff, IL
- Average sea temperature in December: 41.7°F
The best month for swimming (with the highest average sea temperature) is August (73.3°F).
The coldest month (with the lowest average sea temperature) is February (37.1°F).
Average daylight in December /
Average sunshine in December
Lake Bluff, IL
- Average daylight in December: 9h and 6min
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 6min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in December
Lake Bluff, IL
- Average sunshine days in December: 15.3 days
The month with the most sunshine days is December (15.3 days).
The month with the least sunshine days is April (10.8 days).
Average UV index in December
Lake Bluff, IL
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Lake Bluff, IL
- Average cloud cover in December: 58
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are July and August (Cloud cover 27).
Average visibility in December
Lake Bluff, 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).





