December weather forecast
Oak Forest, IL

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Weather in December

December, the first month of the winter in Oak Forest, is still a cold month, with an average temperature ranging between min 25.7°F (-3.5°C) and max 35.4°F (1.9°C).

Temperature

December's arrival comes with a decrease in the average high-temperature, moving from a frosty 46.9°F (8.3°C) in November to a wintry 35.4°F (1.9°C). Throughout December, Oak Forest records an average temperature of 25.7°F (-3.5°C) at night.

Humidity

In Oak Forest, the average relative humidity in December is 81%.

Rainfall

January, February and December are months with the least rain when the rain falls for 4.8 days and typically aggregates up to 0.55" (14mm) of rain.

Snowfall

January through April, October through December are months with snowfall. In Oak Forest, during December, snow falls for 6.6 days and regularly aggregates up to 0.47" (12mm) of snow. Throughout the year, there are 34.2 snowfall days, and 4.8" (122mm) 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, sunrise is at 6:58 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:31 pm CST.

Sunshine

In December, the average sunshine is 4.1h.

UV index

January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 1 suggests this advice:
While many people can endure lengthy sun exposure, it remains imperative to safeguard babies, children, and fair-skinned individuals. Avoiding the Sun during its peak radiation time around midday is a healthy practice. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Updated: Jul 19, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

The average high-temperature, in December, in Oak Forest, is 35.4°F (1.9°C), while the average low-temperature is 25.7°F (-3.5°C). In July, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is calculated to be 87.8°F (31°C).

What is the average humidity in December?

In Oak Forest, the average relative humidity in December is 81%.

What is the driest month?

January, February and December are months with the least rain when the rain falls for 4.8 days and typically aggregates up to 0.55" (14mm) of rain.

How much does it rain in December?

In Oak Forest, in December, during 4.8 rainfall days, 0.55" (14mm) of precipitation is typically accumulated.

How much does it snow in December?

In December, it is snowing for 6.6 days. Throughout December, 0.47" (12mm) of snow is accumulated.

What is the month with the shortest days?

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

How many hours of daylight does Oak Forest have in December?

In Oak Forest, the average day length in December is 9h and 13min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 6:58 am and sunset at 4:21 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 4:31 pm CST.

How long on average sun shines in December?

The average sunshine duration in December is 4.1h.

What are the months with the lowest UV index?

January and December, with an average maximum UV index of 1, are months with the lowest UV index.

How high is the UV index in December?

The average daily maximum UV index in December is 1. A UV Index estimate of 2, and below, represents a low health threat from unprotected exposure to UV radiation.
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 Forest, IL

Average temperature in December - Oak Forest, IL
  • Average high temperature in December: 35.4°F

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in December: 25.7°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.7°F).

Average pressure in December
Oak Forest, IL

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

Average wind speed in December - Oak Forest, IL
  • Average wind speed in December: 9.4mph

The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).

Average humidity in December
Oak Forest, IL

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

The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).

Average rainfall in December
Oak Forest, IL

Average rainfall in December - Oak Forest, IL
  • Average rainfall in December: 0.55"

The wettest month (with the highest rainfall) is May (1.54").
The driest months (with the least rainfall) are January, February and December (0.55").

Average rainfall days in December
Oak Forest, IL

Average rainfall days in December - Oak Forest, IL
  • Average rainfall days in December: 4.8 days

The month with the highest number of rainy days is July (14.1 days).
The month with the least rainy days is February (4.1 days).

Average snowfall in December
Oak Forest, IL

Average snowfall in December - Oak Forest, IL
  • Average snowfall in December: 0.47"

The month with the highest snowfall is January (1.3").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Oak Forest, IL

Average snowfall days in December - Oak Forest, IL
  • Average snowfall days in December: 6.6 days

The month with the highest number of snowfall days is January (10.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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

Average daylight in December / Average sunshine in December - Oak Forest, IL
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 6min).
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 Forest, IL

Average sunshine days in December - Oak Forest, IL
  • Average sunshine days in December: 20.6 days

The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is June (13.1 days).

Average UV index in December
Oak Forest, IL

Average UV index in December - Oak Forest, IL
  • Average UV index in December: 1

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in December
Oak Forest, IL

Average cloud cover in December - Oak Forest, IL
  • Average cloud cover in December: 58

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in December
Oak Forest, IL

Average visibility in December - Oak Forest, 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 Forest, Illinois, USA

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