December weather forecast
River Forest, IN

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Weather in December

December, the first month of the winter in River Forest, is also an icy month, with temperature in the range of an average high of 38.1°F (3.4°C) and an average low of 27.5°F (-2.5°C).

Temperature

With December's onset, the average high-temperature recedes from November's frosty 48.6°F (9.2°C) to an icy 38.1°F (3.4°C). An average minimum temperature of 27.5°F (-2.5°C) is recorded during the month of December.

Humidity

January and December, with an average relative humidity of 83%, are the most humid months.

Rainfall

In River Forest, in December, during 8.3 rainfall days, 1.46" (37mm) of precipitation is typically accumulated. In River Forest, during the entire year, the rain falls for 142.1 days and collects up to 20.91" (531mm) of precipitation.

Snowfall

Months with snowfall are January through April, October through December. The months with the most snowfall are February and December, with an average 2.17" (55mm) of accumulated snow.

Daylight

The month with the shortest days is December, with an average of 9h and 24min of daylight.
On the first day of December, sunrise is at 7:46 am and sunset at 5:17 pm. On the last day of the month, sunrise is at 8:04 am and sunset at 5:27 pm EST.

Sunshine

In December, the average sunshine is 4.1h.

UV index

The months with the lowest UV index are January, February, October through December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 2 suggests this advice:
While most individuals can withstand prolonged sun exposure, it is imperative that babies, children, and those with sensitive skin always be shielded. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Enhance your sun protection with tightly woven, yet airy clothing. Be careful! The Sun's UV radiation can nearly be doubled by the reflective quality of snow.
Updated: Jul 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold does it get in River Forest in December?

The average high-temperature and low-temperature during December are 38.1°F (3.4°C) and 27.5°F (-2.5°C) respectively. In July, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is appraised at 87.8°F (31°C).

What is the most humid month?

The months with the highest humidity are January and December, with an average relative humidity of 83%.

What is the average humidity in December in River Forest?

In River Forest, the average relative humidity in December is 83%.

How many days does it rain in December in River Forest?

In December, the rain falls for 8.3 days. Throughout December, 1.46" (37mm) of precipitation is accumulated.

What is the snowiest month?

The months with the most snowfall are February and December, with an average 2.17" (55mm) of accumulated snow.

How many days does it snow in December?

In River Forest, during December, snow falls for 7.7 days and regularly aggregates up to 2.17" (55mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 24min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 23min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:46 am and sunset at 5:17 pm. On the last day of the month, sunrise is at 8:04 am and sunset at 5:27 pm EST.

How many hours of sunshine does River Forest have in December?

In River Forest, the average sunshine duration in December is 4.1h.

When is the lowest UV index?

The months with the lowest UV index are January, February, October through December, with an average maximum UV index of 2.

How high is the UV index in December?

In River Forest, the average daily maximum UV index in December is 2. A UV Index value of 2, and less, symbolizes a low health risk from 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
River Forest, IN

Average temperature in December - River Forest, IN
  • Average high temperature in December: 38.1°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (32.2°F).

  • Average low temperature in December: 27.5°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (20.5°F).

Average pressure in December
River Forest, IN

Average pressure in December - River Forest, IN
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in December
River Forest, IN

Average wind speed in December - River Forest, IN
  • Average wind speed in December: 9.5mph

The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).

Average humidity in December
River Forest, IN

Average humidity in December - River Forest, IN
  • Average humidity in December: 83%

The months with the highest relative humidity are January and December (83%).
The month with the lowest relative humidity is October (74%).

Average rainfall in December
River Forest, IN

Average rainfall in December - River Forest, IN
  • Average rainfall in December: 1.46"

The wettest month (with the highest rainfall) is May (2.68").
The driest months (with the least rainfall) are February and November (1.14").

Average rainfall days in December
River Forest, IN

Average rainfall days in December - River Forest, IN
  • Average rainfall days in December: 8.3 days

The month with the highest number of rainy days is May (17.6 days).
The month with the least rainy days is February (6.1 days).

Average snowfall in December
River Forest, IN

Average snowfall in December - River Forest, IN
  • Average snowfall in December: 2.17"

The months with the highest snowfall are February and December (2.17").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
River Forest, IN

Average snowfall days in December - River Forest, IN
  • Average snowfall days in December: 7.7 days

The month with the highest number of snowfall days is January (10.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
River Forest, IN

Average daylight in December / Average sunshine in December - River Forest, IN
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in December: 4h and 1min

The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

Average sunshine days in December
River Forest, IN

Average sunshine days in December - River Forest, IN
  • Average sunshine days in December: 15.9 days

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (10.7 days).

Average UV index in December
River Forest, IN

Average UV index in December - River Forest, IN
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).

Average cloud cover in December
River Forest, IN

Average cloud cover in December - River Forest, IN
  • Average cloud cover in December: 58

The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are June, July and August (Cloud cover 32).

Average visibility in December
River Forest, IN

Average visibility in December - River Forest, IN
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).

River Forest, Indiana, USA

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