December weather forecast
Bartlett, IL

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Weather in December

The first month of the winter, December, is also an icy month in Bartlett, Illinois, with an average temperature fluctuating between 34°F (1.1°C) and 23.9°F (-4.5°C).

Temperature

The beginning of December marks a decrease in the average high-temperature, transitioning from a chilly 45.5°F (7.5°C) in November to a cold 34°F (1.1°C). During December, the temperature is averaged to a low of 23.9°F (-4.5°C) at night.

Humidity

In December, the average relative humidity is 81%.

Rainfall

The month with the least rainfall is December, when the rain falls for 7.2 days and typically collects 1.02" (26mm) of precipitation.

Snowfall

Months with snowfall in Bartlett are January through May, October through December. In Bartlett, during December, snow falls for 10.6 days and regularly aggregates up to 2.13" (54mm) of snow. Throughout the year, there are 46.4 snowfall days, and 13.03" (331mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 12min of daylight.
On the first day of the month, sunrise is at 7:01 am and sunset at 4:22 pm. On the last day of December, sunrise is at 7:20 am and sunset at 4:31 pm CST.

Sunshine

The average sunshine in December is 3.9h.

UV index

The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.
Note: In December, the average maximum UV index of 1 translates into the following recommendations:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. It's recommended to limit sun exposure when its radiation is at its peak during midday. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.

Frequently asked questions

How cold is December?

The high-temperature, in December, in Bartlett, is 34°F (1.1°C), while the low-temperature averages to 23.9°F (-4.5°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), which factors the actual air temperature with the relative humidity, in July is calculated to be 87.8°F (31°C).

What is the average humidity in December?

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

What is the driest month?

December is the month with the least rainfall. Rain falls for 7.2 days and accumulates 1.02" (26mm) of precipitation.

How much does it rain in December?

In December, the rain falls for 7.2 days. Throughout December, 1.02" (26mm) of precipitation is accumulated.

How many days does it snow in December?

In Bartlett, in December, snow falls for 10.6 days, with typically accumulated 2.13" (54mm) 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.

How many hours of daylight does Bartlett have in December?

In December, the average day length is 9h and 11min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:01 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 4:31 pm CST.

How many hours of sunshine does Bartlett have in December?

The average sunshine duration in December is 3.9h.

When is the lowest UV index?

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

What is the UV index intensity in December?

The average daily maximum UV index in December is 1. A UV Index of 2, and less, symbolizes a low health threat from exposure to the Sun's 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
Bartlett, IL

Average temperature in December - Bartlett, IL
  • Average high temperature in December: 34°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 (27.7°F).

  • Average low temperature in December: 23.9°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 (16.3°F).

Average pressure in December
Bartlett, IL

Average pressure in December - Bartlett, 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
Bartlett, IL

Average wind speed in December - Bartlett, IL
  • Average wind speed in December: 9.2mph

The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).

Average humidity in December
Bartlett, IL

Average humidity in December - Bartlett, IL
  • Average humidity in December: 81%

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

Average rainfall in December
Bartlett, IL

Average rainfall in December - Bartlett, IL
  • Average rainfall in December: 1.02"

The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is December (1.02").

Average rainfall days in December
Bartlett, IL

Average rainfall days in December - Bartlett, IL
  • Average rainfall days in December: 7.2 days

The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is February (4.8 days).

Average snowfall in December
Bartlett, IL

Average snowfall in December - Bartlett, IL
  • Average snowfall in December: 2.13"

The month with the highest snowfall is January (3.39").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
Bartlett, IL

Average snowfall days in December - Bartlett, IL
  • Average snowfall days in December: 10.6 days

The month with the highest number of snowfall days is January (12.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Bartlett, IL

Average daylight in December / Average sunshine in December - Bartlett, 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: 3h and 5min

The months with the most sunshine are July and August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).

Average sunshine days in December
Bartlett, IL

Average sunshine days in December - Bartlett, IL
  • Average sunshine days in December: 15.6 days

The month with the most sunshine days is November (17.6 days).
The month with the least sunshine days is July (10.9 days).

Average UV index in December
Bartlett, IL

Average UV index in December - Bartlett, IL
  • Average UV index in December: 1

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

Average cloud cover in December
Bartlett, IL

Average cloud cover in December - Bartlett, IL
  • Average cloud cover in December: 60

The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July, August and September (Cloud cover 33).

Average visibility in December
Bartlett, IL

Average visibility in December - Bartlett, IL
  • Average visibility in December: 6mi

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

Bartlett, Illinois, USA

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