Chicago
Illinois, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Chicago, IL

An aerial view of the city of Chicago in Illinois, on the shores of Lake Michigan, with a superb view of the sandy beach of Oak Street
An aerial view of the city of Chicago in Illinois, on the shores of Lake Michigan, with a superb view of the sandy beach of Oak Street
The first month of the winter, December, is still a cold month in Chicago, Illinois, with average temperature fluctuating between 35.8°F (2.1°C) and 27.9°F (-2.3°C).

Temperature

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

Humidity

The average relative humidity in December is 80%.

Rainfall

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

Snowfall

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

Ocean temperature

In December, the average ocean temperature is 42.4°F (5.8°C).
Note: 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.

Daylight

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

Sunshine

In Chicago, the average sunshine is 4h.

UV index

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Chicago. A UV Index of 2, and less, symbolizes a minimal health hazard from unsafe exposure to the UV radiation for average individuals.
Note: The average daily UV index of 1 in December transform into the following instructions:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always 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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in December in Chicago?

In Chicago, Illinois, in December, 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?

In Chicago, the average relative humidity in December is 80%.

How many days does it rain in December in Chicago?

In Chicago, during December, the rain falls for 8.8 days and regularly aggregates up to 1.65" (42mm) of precipitation.

What is the driest month in Chicago?

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

How many days does it snow in December in Chicago?

In Chicago, in December, snow falls for 7.5 days, with typically accumulated 2.52" (64mm) of snow.

What is the ocean temperature in December in Chicago?

In Chicago, Illinois, in December, the average water temperature 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?

The month with the shortest days in Chicago is December, 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 is 9.2h.

How long on average sun shines in December in Chicago?

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

What is the month 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 intensity in December in Chicago?

The average daily maximum UV index in December in Chicago, Illinois, is 1. A UV Index reading of 2, and below, represents a low health risk from unprotected exposure to the UV radiation.
Average temperature in December - Chicago, IL
  • Average high temperature in December: 35.8°F

The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is January (29.7°F).

  • Average low temperature in December: 27.9°F

The month with the highest average low temperature is July (67.8°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).

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%).

Average rainfall in December - Chicago, IL
  • Average rainfall in December: 1.65"

The wettest month (with the highest rainfall) is June (4.88").
The driest month (with the lowest rainfall) is December (1.65").

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 lowest number of rainy days is February (5.5 days).

Average snowfall in December - Chicago, IL
  • Average snowfall in December: 2.52"

The month with the highest snowfall is February (3.54").
Months with the lowest snowfall are June, July, August, September and October (0").

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 lowest number of snowfall days are June, July, August and September (0 days).

Average sea temperature in December - Chicago, IL
  • Average sea temperature in December: 42.4°F

The best month for swimming (with the highest average sea temperature) is August (73.9°F).
The coldest month (with the lowest average sea temperature) is February (36.9°F).

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 shortest days is December (Average daylight: 9.2h).

  • Average sunshine in December: 4h

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

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).