December weather forecast
Oak Brook, IL

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Weather in December

The first month of the winter, December, is also a wintry month in Oak Brook, Illinois, with an average temperature varying between 34.5°F (1.4°C) and 25°F (-3.9°C).

Temperature

December suggests a modest reduction in the average high-temperature, shifting from a chilly 45.7°F (7.6°C) in November to a cold 34.5°F (1.4°C). December's nights observe an average temperature of 25°F (-3.9°C).

Humidity

The average relative humidity in December is 81%.

Rainfall

December is the month with the least rainfall. Rain falls for 4.9 days and accumulates 0.63" (16mm) of precipitation.

Snowfall

Months with snowfall are January through April, October through December. In Oak Brook, in December, during 7.2 snowfall days, 0.75" (19mm) of snow is typically accumulated. Throughout the year, there are 34.9 snowfall days, and 7.2" (183mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 12min of daylight.
On the first day of December in Oak Brook, sunrise is at 7:00 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:31 pm CST.

Sunshine

In December, the average sunshine is 4.1h.

UV index

The average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum UV index of 2 during December leads to these instructions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Updated: Jul 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

The high-temperature, in December, in Oak Brook, records 34.5°F (1.4°C), while the low-temperature is 25°F (-3.9°C). The average heat index (a.k.a. 'feels like', 'apparent temperature'), which combines relative humidity and air temperature, in August is appraised at 86°F (30°C).

What is the average humidity in December?

In December, the average relative humidity is 81%.

What is the driest month?

December is the month with the least rainfall. Rain falls for 4.9 days and accumulates 0.63" (16mm) of precipitation.

How many days does it rain in December in Oak Brook?

In Oak Brook, Illinois, in December, it is raining for 4.9 days, with typically 0.63" (16mm) of accumulated precipitation.

How many days does it snow in December in Oak Brook?

In Oak Brook, in December, snow falls for 7.2 days, with typically accumulated 0.75" (19mm) of snow.

What is the month with the shortest days?

With an average of 9h and 12min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In Oak Brook, the average day length in December is 9h and 12min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:00 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:31 pm CST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.1h.

What is the UV index reading in December?

In Oak Brook, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Oak Brook, IL

Average temperature in December - Oak Brook, IL
  • Average high temperature in December: 34.5°F

The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (28.8°F).

  • Average low temperature in December: 25°F

The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).

Average pressure in December
Oak Brook, IL

Average pressure in December - Oak Brook, 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
Oak Brook, IL

Average wind speed in December - Oak Brook, IL
  • Average wind speed in December: 9mph

The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

Average humidity in December
Oak Brook, IL

Average humidity in December - Oak Brook, IL
  • Average humidity in December: 81%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

Average rainfall in December
Oak Brook, IL

Average rainfall in December - Oak Brook, IL
  • Average rainfall in December: 0.63"

The wettest month (with the highest rainfall) is May (1.97").
The driest month (with the least rainfall) is December (0.63").

Average rainfall days in December
Oak Brook, IL

Average rainfall days in December - Oak Brook, IL
  • Average rainfall days in December: 4.9 days

The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (4.2 days).

Average snowfall in December
Oak Brook, IL

Average snowfall in December - Oak Brook, IL
  • Average snowfall in December: 0.75"

The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Oak Brook, IL

Average snowfall days in December - Oak Brook, IL
  • Average snowfall days in December: 7.2 days

The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Oak Brook, IL

Average daylight in December / Average sunshine in December - Oak Brook, 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: 4h and 1min

The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in December
Oak Brook, IL

Average sunshine days in December - Oak Brook, IL
  • Average sunshine days in December: 20.7 days

The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is July (11.8 days).

Average UV index in December
Oak Brook, IL

Average UV index in December - Oak Brook, IL
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).

Average cloud cover in December
Oak Brook, IL

Average cloud cover in December - Oak Brook, IL
  • Average cloud cover in December: 59

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).

Average visibility in December
Oak Brook, IL

Average visibility in December - Oak Brook, 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).

Oak Brook, Illinois, USA

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