December weather forecast
Raritan, IL

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Weather in December

December, the first month of the winter in Raritan, is also a wintry month, with an average temperature ranging between min 25.5°F (-3.6°C) and max 37°F (2.8°C).

Temperature

December's arrival correlates with a reduction in the average high-temperature, down from a chilly 48.9°F (9.4°C) in November to an icy 37°F (2.8°C). Raritan, in the month of December, anticipates a consistent average low-temperature of 25.5°F (-3.6°C).

Humidity

The average relative humidity in December is 79%.

Rainfall

In Raritan, during December, the rain falls for 5.6 days and regularly aggregates up to 0.98" (25mm) of precipitation. Throughout the year, in Raritan, there are 127.6 rainfall days, and 21.02" (534mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through April, October through December. In Raritan, in December, during 5.4 snowfall days, 1.3" (33mm) of snow is typically accumulated. Throughout the year, there are 26.4 snowfall days, and 9.06" (230mm) of snow is accumulated.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:08 am and sunset at 4:36 pm. On the last day of December, sunrise is at 7:27 am and sunset at 4:46 pm CST.

Sunshine

In December, the average sunshine is 4.5h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: A daily maximum UV index of 2 in December translates into the following instructions:
Prolonged sun exposure should always be prevented in babies, children, and those with sensitive skin. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
Updated: Jun 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

In December, in Raritan, the average high-temperature is 37°F (2.8°C), and the average low-temperature is 25.5°F (-3.6°C). In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines relative humidity and air temperature, is computed to be 89.6°F (32°C).

What is the average humidity in December?

In Raritan, the average relative humidity in December is 79%.

How many days does it rain in December?

In December, the rain falls for 5.6 days. Throughout December, 0.98" (25mm) of precipitation is accumulated.

How many days does it snow in December?

In Raritan, during December, snow falls for 5.4 days and regularly aggregates up to 1.3" (33mm) of snow.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

What is the average length of the day in December?

In Raritan, the average day length in December is 9h and 19min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:08 am and sunset at 4:36 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:46 pm CST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.5h.

When is the lowest UV index?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the UV index reading in December?

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability 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
Raritan, IL

Average temperature in December - Raritan, IL
  • Average high temperature in December: 37°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is January (30.9°F).

  • Average low temperature in December: 25.5°F

The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (18.7°F).

Average pressure in December
Raritan, IL

Average pressure in December - Raritan, IL
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in December
Raritan, IL

Average wind speed in December - Raritan, IL
  • Average wind speed in December: 10.1mph

The windiest month (with the highest average wind speed) is January (10.6mph).
The calmest months (with the lowest average wind speed) are July and August (6.7mph).

Average humidity in December
Raritan, IL

Average humidity in December - Raritan, IL
  • Average humidity in December: 79%

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

Average rainfall in December
Raritan, IL

Average rainfall in December - Raritan, IL
  • Average rainfall in December: 0.98"

The wettest month (with the highest rainfall) is May (3.11").
The driest month (with the least rainfall) is January (0.83").

Average rainfall days in December
Raritan, IL

Average rainfall days in December - Raritan, IL
  • Average rainfall days in December: 5.6 days

The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (4.3 days).

Average snowfall in December
Raritan, IL

Average snowfall in December - Raritan, IL
  • Average snowfall in December: 1.3"

The month with the highest snowfall is January (3.15").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Raritan, IL

Average snowfall days in December - Raritan, IL
  • Average snowfall days in December: 5.4 days

The month with the highest number of snowfall days is January (8.5 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
Raritan, IL

Average daylight in December / Average sunshine in December - Raritan, IL
  • 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 18min).

  • Average sunshine in December: 4h and 3min

The months with the most sunshine are June and July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days in December
Raritan, IL

Average sunshine days in December - Raritan, IL
  • Average sunshine days in December: 20 days

The month with the most sunshine days is December (20 days).
The months with the least sunshine days are May and June (11.8 days).

Average UV index in December
Raritan, IL

Average UV index in December - Raritan, IL
  • 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, November and December (UV index 2).

Average cloud cover in December
Raritan, IL

Average cloud cover in December - Raritan, IL
  • Average cloud cover in December: 51

The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are August and September (Cloud cover 30).

Average visibility in December
Raritan, IL

Average visibility in December - Raritan, 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).

Raritan, Illinois, USA

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