December weather forecastNorthbrook, IL
December
Weather in December
December, the first month of the winter in Northbrook, is also a wintry month, with an average temperature varying between 26.1°F (-3.3°C) and 34.9°F (1.6°C).Temperature
The shift to December brings a decrease in the average high-temperature, falling from a chilly 45.5°F (7.5°C) in November to a cold 34.9°F (1.6°C). Northbrook's nocturnal average in December closely mirrors its daytime temperatures, settling at a subzero cold 26.1°F (-3.3°C).Humidity
The average relative humidity in December is 80%.Rainfall
December is the month with the least rainfall. Rain falls for 9.1 days and accumulates 1.65" (42mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Northbrook, in December, snow falls for 10 days, with typically accumulated 2.99" (76mm) of snow. In Northbrook, during the entire year, snow falls for 47.6 days and aggregates up to 17.8" (452mm) 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 7:00 am and sunset at 4:20 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:29 pm CST.
Sunshine
In Northbrook, the average sunshine in December is 4h.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 unsafe exposure to UV radiation for ordinary individuals.Note: The maximum UV index of 1 during December leads to these instructions:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Northbrook, IL
- Average high temperature in December: 34.9°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in December: 26.1°F
The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Northbrook, IL
- Average pressure in December: 30.09"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
Northbrook, IL
- Average wind speed in December: 10.7mph
The windiest month (with the highest average wind speed) is January (11.5mph).
The calmest month (with the lowest average wind speed) is August (7.1mph).
Average humidity in December
Northbrook, IL
- Average humidity in December: 80%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in December
Northbrook, IL
- Average rainfall in December: 1.65"
The wettest months (with the highest rainfall) are May and June (4.57").
The driest month (with the least rainfall) is December (1.65").
Average rainfall days in December
Northbrook, IL
- Average rainfall days in December: 9.1 days
The month with the highest number of rainy days is May (19.1 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in December
Northbrook, IL
- Average snowfall in December: 2.99"
The month with the highest snowfall is January (4.84").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Northbrook, IL
- Average snowfall days in December: 10 days
The month with the highest number of snowfall days is January (13.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Northbrook, IL
- Average daylight in December: 9h and 12min
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: 4h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in December
Northbrook, IL
- Average sunshine days in December: 14.3 days
The month with the most sunshine days is November (15.5 days).
The month with the least sunshine days is June (9.2 days).
Average UV index in December
Northbrook, 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
Northbrook, 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 28).
Average visibility in December
Northbrook, 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).
