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

January 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
January, the same as December, in Chicago, Illinois, is another subzero cold winter month, with average temperature fluctuating between 20.7°F (-6.3°C) and 29.7°F (-1.3°C).

Temperature

January is the coldest month, with an average high-temperature of 29.7°F (-1.3°C) and an average low-temperature of 20.7°F (-6.3°C).

Humidity

With an average relative humidity of 82%, January is the most humid month in Chicago.

Rainfall

In Chicago, during January, the rain falls for 6.6 days and regularly aggregates up to 1.77" (45mm) of precipitation. In Chicago, Illinois, during the entire year, the rain falls for 160.2 days and collects up to 36.97" (939mm) of precipitation.

Snowfall

Months with snowfall in Chicago are January through May, November and December. In Chicago, during 10.6 snowfall days, 3.39" (86mm) of snow is typically accumulated. In Chicago, during the entire year, snow falls for 40.9 days, and aggregates up to 13.9" (353mm) of snow.

Ocean temperature

In January, the average ocean temperature in Chicago is 39°F (3.9°C).
Note: For swimming, this is considered extremely cold, dangerous, and life-threatening. Unless suitably protected with insulated waterproof clothing, hypothermia quickly occurs.

Daylight

In Chicago, the average length of the day is 9.5h.

Sunshine

With an average of 3.7h of sunshine, January has the least sunshine of the year.

UV index

January and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a low threat to health from the exposure to the Sun's UV radiation for average individuals.
Note: The daily maximum UV index of 1 in January interpret into the following advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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 coldest month in Chicago?

January is the coldest month, with an average high-temperature of 29.7°F (-1.3°C) and an average low-temperature of 20.7°F (-6.3°C).

What is the temperature in January in Chicago?

The average high-temperature, in January, in Chicago, is 29.7°F (-1.3°C), while the average low-temperature is 20.7°F (-6.3°C).

What is the most humid month in Chicago?

The most humid month is January, with an average relative humidity of 82%.

What is the average humidity in January in Chicago?

In January, the average relative humidity is 82%.

How many days does it rain in January in Chicago?

In Chicago, during January, the rain falls for 6.6 days and regularly aggregates up to 1.77" (45mm) of precipitation.

How much does it snow in Chicago in January?

In Chicago, in January, during 10.6 snowfall days, 3.39" (86mm) of snow is typically accumulated.

How cold is the water in January in Chicago?

In Chicago, the average seawater temperature in January is 39°F (3.9°C). For swimming, this is considered extremely cold, dangerous, and life-threatening. Unless suitably protected with insulated waterproof clothing, hypothermia quickly occurs.

How many hours of daylight does Chicago have in January?

In January, the average length of the day in Chicago, Illinois, is 9.5h.

What is the month with the least sunshine in Chicago?

The month with the least sunshine in Chicago, Illinois, is January, with an average of 3.7h of sunshine.

How many hours of sunshine does Chicago have in January?

The average sunshine in January is 3.7h.

When is the lowest UV index in Chicago?

Months with the lowest UV index in Chicago, Illinois, are January and December, with an average maximum UV index of 1.

What is the UV index intensity in January in Chicago?

In Chicago, Illinois, the average daily maximum UV index in January is 1. A UV Index estimate of 2, and below, represents a low health threat from unprotected exposure to the UV radiation.
Average temperature in January - Chicago, IL
  • Average high temperature in January: 29.7°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 January: 20.7°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 January - Chicago, IL
  • Average humidity in January: 82%

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

Average rainfall in January - Chicago, IL
  • Average rainfall in January: 1.77"

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 January - Chicago, IL
  • Average rainfall days in January: 6.6 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 January - Chicago, IL
  • Average snowfall in January: 3.39"

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 January - Chicago, IL
  • Average snowfall days in January: 10.6 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 January - Chicago, IL
  • Average sea temperature in January: 39°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 January / Average sunshine in January - Chicago, IL
  • Average daylight in January: 9.5h

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 January: 3.7h

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 January - Chicago, IL
  • Average UV index in January: 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).