December weather forecastSunny Hill, IL

December

Weather in December

The first month of the winter, December, is still a cold month in Sunny Hill, Illinois, with temperature in the range of an average high of 34.7°F (1.5°C) and an average low of 24.1°F (-4.4°C).

Temperature

December brings a decrease in the average high-temperature, falling from November's frosty 46.9°F (8.3°C) to a wintry 34.7°F (1.5°C). During the month of December, an average low-temperature of 24.1°F (-4.4°C) is recorded.

Humidity

In Sunny Hill, the average relative humidity in December is 81%.

Rainfall

The month with the least rainfall is December, when the rain falls for 7.4 days and typically collects 1.26" (32mm) of precipitation.

Snowfall

Months with snowfall are January through April, October through December. In Sunny Hill, Illinois, in December, snow falls for 7.5 days, with typically accumulated 1.97" (50mm) of snow. In Sunny Hill, Illinois, during the entire year, snow falls for 36.5 days and aggregates up to 13.5" (343mm) 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 7:08 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:42 pm CST.

Sunshine

The average sunshine in December is 4.3h.

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 minimal health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: The UV index of 1 during December translates into the following guidance:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. To guard against the harmful effects of the Sun, minimize exposure during midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Updated: Aug 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

December temperatures vary between a high-temperature of 34.7°F (1.5°C) and a low-temperature of 24.1°F (-4.4°C). In July, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is calculated to be 87.8°F (31°C).

In December, the average relative humidity is 81%.

December is the month with the least rainfall. Rain falls for 7.4 days and accumulates 1.26" (32mm) of precipitation.

In Sunny Hill, during December, the rain falls for 7.4 days and regularly aggregates up to 1.26" (32mm) of precipitation.

In December, it is snowing for 7.5 days. Throughout December, 1.97" (50mm) of snow is accumulated.

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

The average day length in December is 9h and 14min.

In December, on the first day of the month, sunrise is at 7:08 am and sunset at 4:32 pm. On the last day of the month, in Sunny Hill, sunrise is at 7:27 am and sunset at 4:42 pm CST.

In December, the average sunshine duration is 4.3h.

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

The average daily maximum UV index in December is 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Sunny Hill, IL

  • Average high temperature in December: 34.7°F

The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (28.4°F).

  • Average low temperature in December: 24.1°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).

Average pressure in December
Sunny Hill, IL

  • 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 (29.9"Hg).

Average wind speed in December
Sunny Hill, IL

  • Average wind speed in December: 9.9mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.7mph).

Average humidity in December
Sunny Hill, IL

  • Average humidity in December: 81%

The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (71%).

Average rainfall in December
Sunny Hill, IL

  • Average rainfall in December: 1.26"

The wettest month (with the highest rainfall) is May (4.45").
The driest month (with the least rainfall) is December (1.26").

Average rainfall days in December
Sunny Hill, IL

  • Average rainfall days in December: 7.4 days

The month with the highest number of rainy days is May (18.2 days).
The month with the least rainy days is January (5 days).

Average snowfall in December
Sunny Hill, IL

  • Average snowfall in December: 1.97"

The month with the highest snowfall is January (4.09").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Sunny Hill, IL

  • Average snowfall days in December: 7.5 days

The month with the highest number of snowfall days is January (11.2 days).
The months with the least snowfall days are May, June, July and August (0 days).

Average daylight in December /
Average sunshine in December
Sunny Hill, IL

  • Average daylight in December: 9h and 12min

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 18min

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

Average sunshine days in December
Sunny Hill, IL

  • Average sunshine days in December: 17.8 days

The month with the most sunshine days is November (17.9 days).
The month with the least sunshine days is May (10.4 days).

Average UV index in December
Sunny Hill, IL

  • Average UV index in December: 1

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

Average cloud cover in December
Sunny Hill, IL

  • Average cloud cover in December: 54

The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in December
Sunny Hill, 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).