December weather forecast
Downers Grove, IL

Weather in December

December, the first month of the winter in Downers Grove, is still a cold month, with an average temperature varying between 25°F (-3.9°C) and 34.5°F (1.4°C).

Temperature

In December, the average high-temperature decreases from a chilly 45.7°F (7.6°C) in November to a wintry 34.5°F (1.4°C). The average low-temperature, in December, is 25°F (-3.9°C).

Humidity

In Downers Grove, Illinois, the average relative humidity in December is 81%.

Rainfall

The month with the least rainfall is December, when the rain falls for 4.9 days and typically collects 0.63" (16mm) of precipitation.

Snowfall

Months with snowfall are January through April, October through December. In Downers Grove, in December, during 7.2 snowfall days, 0.75" (19mm) of snow is typically accumulated. Throughout the year, in Downers Grove, Illinois, there are 34.9 snowfall days, and 7.2" (183mm) of snow is accumulated.

Daylight

December has the shortest days of the year in Downers Grove, with an average of 9h and 12min of daylight.
On the first day of December in Downers Grove, Illinois, sunrise is at 7:00 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:30 pm CST.

Sunshine

The average sunshine in December is 4.1h.

UV index

In Downers Grove, Illinois, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In December, the average maximum UV index of 2 translate into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the average humidity in December in Downers Grove?

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

What is the driest month in Downers Grove?

The month with the least rainfall in Downers Grove is December, when the rain falls for 4.9 days and typically collects 0.63" (16mm) of precipitation.

How many days does it rain in December in Downers Grove?

In Downers Grove, Illinois, in December, during 4.9 rainfall days, 0.63" (16mm) of precipitation is typically accumulated.

How many days does it snow in December in Downers Grove?

In December, it is snowing for 7.2 days. Throughout December, 0.75" (19mm) of snow is accumulated.

What is the month with the shortest days in Downers Grove?

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

How many hours of daylight does Downers Grove have in December?

In December, the average day length in Downers Grove is 9h and 12min.

When is the sunrise / sunset in December in Downers Grove?

On the first day of December, sunrise is at 7:00 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 4:30 pm CST.

How long on average sun shines in December in Downers Grove?

The average sunshine duration in December in Downers Grove, Illinois, is 4.1h.

How high is the UV index in December in Downers Grove?

The average daily maximum UV index in December in Downers Grove, Illinois, is 2. A UV Index reading of 2, and below, represents a low health threat from unprotected exposure to UV radiation.

Average temperature in December
Downers Grove, IL

Average temperature in December - Downers Grove, IL
  • Average high temperature in December: 34.5°F

The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (28.8°F).

  • Average low temperature in December: 25°F

The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).

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Average pressure in December
Downers Grove, IL

Average pressure in December - Downers Grove, 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).

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Average wind speed in December
Downers Grove, IL

Average wind speed in December - Downers Grove, IL
  • Average wind speed in December: 9mph

The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

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Average humidity in December
Downers Grove, IL

Average humidity in December - Downers Grove, IL
  • Average humidity in December: 81%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in December
Downers Grove, IL

Average rainfall in December - Downers Grove, IL
  • Average rainfall in December: 0.63"

The wettest month (with the highest rainfall) is May (1.97").
The driest month (with the least rainfall) is December (0.63").

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Average rainfall days in December
Downers Grove, IL

Average rainfall days in December - Downers Grove, IL
  • Average rainfall days in December: 4.9 days

The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (4.2 days).

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Average snowfall in December
Downers Grove, IL

Average snowfall in December - Downers Grove, IL
  • Average snowfall in December: 0.75"

The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in December
Downers Grove, IL

Average snowfall days in December - Downers Grove, IL
  • Average snowfall days in December: 7.2 days

The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in December /
Average sunshine in December
Downers Grove, IL

Average daylight in December / Average sunshine in December - Downers Grove, IL
  • Average daylight in December: 9h and 12min

The month with the longest days is June (Average daylight: 15h and 10min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in December: 4.1h

The month with the most sunshine is August (Average sunshine: 10h).
The month with the least sunshine is January (Average sunshine: 3.7h).

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Average sunshine days in December
Downers Grove, IL

Average sunshine days in December - Downers Grove, IL
  • Average sunshine days in December: 20.7 days

The month with the most sunshine days is December (20.7 days).
The month with the least sunshine days is July (11.8 days).

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Average UV index in December
Downers Grove, IL

Average UV index in December - Downers Grove, IL
  • Average UV index in December: 2

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

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Average cloud cover in December
Downers Grove, IL

Average cloud cover in December - Downers Grove, IL
  • Average cloud cover in December: 59

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 31).

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Average visibility in December
Downers Grove, IL

Average visibility in December - Downers Grove, 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).

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