December weather forecast and climate
Chicago, IL

The city of Chicago in Illinois on the shores of Lake Michigan, with a superb view of the sandy beach of Oak Street
The city of Chicago in Illinois on the shores of Lake Michigan, with a superb view of the sandy beach of Oak Street

Weather in December

December, the first month of the winter, in Chicago, is still a cold month, with average temperature fluctuating between 27.9°F (-2.3°C) and 35.8°F (2.1°C).

Temperature

In December, the average high-temperature decreases, from a chilly 46°F (7.8°C) in November, to a cold 35.8°F (2.1°C). In Chicago, the average low-temperature is 27.9°F (-2.3°C).

Humidity

In Chicago, Illinois, the average relative humidity is 80%.

Rainfall

December is the month with the least rainfall. Rain falls for 8.8 days and accumulates 1.65" (42mm) of precipitation.

Snowfall

Months with snowfall in Chicago are January through May, November and December. In Chicago, during December, snow falls for 7.5 days and regularly aggregates up to 2.52" (64mm) of snow. In Chicago, during the entire year, snow falls for 40.9 days, and aggregates up to 13.9" (353mm) of snow.

Ocean temperature

In December, the average ocean temperature is 42.4°F (5.8°C).
Note: Swimming in 42.4°F (5.8°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

December has the shortest days of the year, with an average of 9.2h of daylight.

Sunshine

In Chicago, Illinois, the average sunshine in December is 4h.

UV index

Months with the lowest UV index in Chicago, Illinois, are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low health risk from unprotected exposure to the Sun's UV rays for the average person.
Note: The daily maximum UV index of 1 interpret into the following advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the temperature in December in Chicago?

In December, in Chicago, the average high-temperature is 35.8°F (2.1°C), and the average low-temperature is 27.9°F (-2.3°C).

What is the average humidity in December in Chicago?

The average relative humidity in December is 80%.

How much does it rain in Chicago in December?

In Chicago, Illinois, in December, it is raining for 8.8 days, with typically 1.65" (42mm) of accumulated precipitation.

What is the driest month in Chicago?

December is the month with the least rainfall. Rain falls for 8.8 days and accumulates 1.65" (42mm) of precipitation.

How much does it snow in Chicago in December?

In December, it is snowing for 7.5 days. Throughout December, 2.52" (64mm) of snow is accumulated.

How cold is the water in December in Chicago?

In December, the average ocean temperature in Chicago is 42.4°F (5.8°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days in Chicago?

December has the shortest days of the year in Chicago, Illinois, with an average of 9.2h of daylight.

How many hours of daylight does Chicago have in December?

In December, the average length of the day in Chicago is 9.2h.

How long on average sun shines in December in Chicago?

The average sunshine in December in Chicago, Illinois, is 4h.

What are the months with the lowest UV index in Chicago?

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

What is the UV index reading in December in Chicago?

In December, the average daily maximum UV index in Chicago, Illinois, is 1. A UV Index reading of 2, and below, represents a minimal hazard to health from unprotected exposure to the UV radiation.

Average temperature in December
Chicago, IL

Average temperature in December - Chicago, IL
  • Average high temperature in December: 2.1°C

The warmest month (with the highest average high temperature) is August (25.3°C).
The month with the lowest average high temperature is January (-1.3°C).

  • Average low temperature in December: -2.3°C

The month with the highest average low temperature is July (19.9°C).
The coldest month (with the lowest average low temperature) is January (-6.3°C).

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Average pressure in December
Chicago, IL

Average pressure in December - Chicago, IL
  • Average pressure in December: 1019mbar

The month with the highest atmospheric pressure is January (1019.5mbar).
The month with the lowest atmospheric pressure is June (1013.3mbar).

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Average wind speed in December
Chicago, IL

Average wind speed in December - Chicago, IL
  • Average wind speed in December: 18.9km/h

The windiest month (with the highest average wind speed) is January (20.1km/h).
The calmest month (with the lowest average wind speed) is July (12.4km/h).

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Average humidity in December
Chicago, IL

Average humidity in December - Chicago, IL
  • Average humidity in December: 80%

The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (73%).

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Average rainfall in December
Chicago, IL

Average rainfall in December - Chicago, IL
  • Average rainfall in December: 42mm

The wettest month (with the highest rainfall) is June (124mm).
The driest month (with the least rainfall) is December (42mm).

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Average rainfall days in December
Chicago, IL

Average rainfall days in December - Chicago, IL
  • Average rainfall days in December: 8.8 days

The month with the highest number of rainy days is July (18.5 days).
The month with the least rainy days is February (5.5 days).

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Average snowfall in December
Chicago, IL

Average snowfall in December - Chicago, IL
  • Average snowfall in December: 64mm

The month with the highest snowfall is February (90mm).
Months with the least snowfall are June, July, August, September and October (0mm).

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Average snowfall days in December
Chicago, IL

Average snowfall days in December - Chicago, IL
  • Average snowfall days in December: 7.5 days

The month with the highest number of snowfall days is January (10.6 days).
Months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in December
Chicago, IL

Average sea temperature in December - Chicago, IL
  • Average sea temperature in December: 5.8°C

The best month for swimming (with the highest average sea temperature) is August (23.3°C).
The coldest month (with the lowest average sea temperature) is February (2.7°C).

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

Average daylight in December / Average sunshine in December - Chicago, IL
  • Average daylight in December: 9.2h

The month with the longest days is June (Average daylight: 15.2h).
The month with the shortest days is December (Average daylight: 9.2h).

  • Average sunshine in December: 4h

Months with the most sunshine are July and August (Average sunshine: 10.6h).
The month with the least sunshine is January (Average sunshine: 3.7h).

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Average sunshine days in December
Chicago, IL

Average sunshine days in December - Chicago, IL
  • Average sunshine days in December: 15.5 days

The month with the most sunshine days is December (15.5 days).
The month with the least sunshine days is July (9.3 days).

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Average UV index in December
Chicago, IL

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

Months with the highest UV index are July and August (UV index 6).
Months with the lowest UV index are January and December (UV index 1).

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Average cloud cover in December
Chicago, IL

Average cloud cover in December - Chicago, IL
  • Average cloud cover in December: 58

The month with the most cloud cover is January (Cloud cover 62).
Months with the least cloud cover are July and August (Cloud cover 27).

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Average visibility in December
Chicago, IL

Average visibility in December - Chicago, IL
  • Average visibility in December: 9km

Months with the highest visibility are September and October (10km).
Months with the lowest visibility are January, February, March, April, May, June, July, August, November and December (9km).

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