Climate and monthly weather forecast
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

The climate of Chicago, IL

Chicago has a hot-summer humid continental type of climate (Köppen climate classification Dfa) with hot and humid summers and cold winters.
It lies in northeastern Illinois, on the southwestern shores of Lake Michigan in the Great Lakes region, and is part of the Midwestern United States. Lake Michigan moderates the climate of Chicago with cooler summers and warmer winters compared to other places in Illinois. Chicago, the Windy City, stretches on the continental divide at the confluence of the Great Lakes and Mississippi river waters. The city is at an average elevation of 176 meters above sea level with naturally flat topography.

Chicago summers tend to be hot as the average high temperature touches 85°F (29.4°C) at the peak of July. High temperatures reach 90°F (32.2°C) for a few days, while they rarely cross 100°F (37.8°C).
Winters are cold with the average low temperature of 17°F (-8.3°C) in January, and even daily highs are sometimes below freezing of 32°F (0°C). The breezes from Lake Michigan have a localized cooling effect on the immediate lakefront neighborhoods; dense fog in the city is a common effect of the breeze during the winter.

Humidity averages 70% over the year, which makes the weather muggy. The sunshine reaches the ground in Chicago for an annual 2400 hours, and generally, 84 days have clear skies during the year. Annual precipitation of 36" (914mm) occurs within 124 rainy days and summers are a little wetter than the other seasons. Snowfall is in the range of 36" (914mm), with an average of 28 snowy days during the year.

The highest officially recorded temperature in Chicago is 105°F (40.6°C) at Midway Airport on July 24, 1934, while the lowest recorded temperature was -27°F (-32.8°C) at O'Hare Airport on January 20, 1985.

The best time to visit Chicago, IL

The best time to visit Chicago is in spring from March to May and in autumn from September to October, although visitors throng the city from March to November.
Spring is wet and warm, while autumn is pleasant with warm days and cold nights. Summer is usually the peak tourist season, but the temperatures are a bit higher than the shoulder seasons, and visitors throng the city in large numbers.

The worst time to visit Chicago, IL

December to February is the worst time to visit Chicago in the cold of winter.
Heavy snowfall occurs during the winter months, and the snowpack becomes at least 3" (76mm) thick. Snowstorms rarely occur in Chicago, but the temperatures drop below 10°F (-12.2°C) for one-fourth of the nights during winter, and few even drop to 0°F (-17.8°C) and below. Summer crowds disperse during the cold months in vast numbers.

Weather hazards

Chicago is amongst the top ten safest cities in the United States, with few incidences of tornadoes, floods, wildfires, or earthquakes. However, spring and summer are prone to thunderstorms, and an average of 38 days during the year witness thunderstorms. Snowstorms rarely occur during the winter, but a single day of 10" (254mm) of snow occurs once in a few years.

Weather in January

January, like December, is a freezing cold winter month in Chicago, Illinois, with an average temperature ranging between max 29.7°F (-1.3°C) and min 20.7°F (-6.3°C). 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). Weather in January »

Weather in February

February, the last month of the winter in Chicago, is a cold month, with an average temperature fluctuating between 23°F (-5°C) and 32°F (0°C). In Chicago, the average high-temperature in February is relatively the same as in January - a wintry 32°F (0°C). Weather in February »

Weather in March

The first month of the spring, March, is still a cold month in Chicago, Illinois, with an average temperature ranging between min 32.2°F (0.1°C) and max 41.5°F (5.3°C). In March, the average high-temperature increases from 32°F (0°C) in February to a still wintry 41.5°F (5.3°C). Weather in March »

Weather in April

April is a fresh spring month in Chicago, Illinois, with an average temperature fluctuating between 40.6°F (4.8°C) and 50.7°F (10.4°C). In Chicago, the average high-temperature in April rises from a cold 41.5°F (5.3°C) in March to a cool 50.7°F (10.4°C). Weather in April »

Weather in May

The last month of the spring, May, is an enjoyable month in Chicago, Illinois, with an average temperature ranging between min 50.4°F (10.2°C) and max 61°F (16.1°C). In May, the average high-temperature increases from a fresh 50.7°F (10.4°C) in April to a comfortable 61°F (16.1°C). Weather in May »

Weather in June

June, the first month of the summer in Chicago, is a pleasant month, with an average temperature varying between 70.5°F (21.4°C) and 60.3°F (15.7°C). In June, the average high-temperature increases from an enjoyable 61°F (16.1°C) in May to a pleasant 70.5°F (21.4°C). Weather in June »

Weather in July

July in Chicago, Illinois, is a moderately hot summer month, with an average temperature varying between 67.8°F (19.9°C) and 77.4°F (25.2°C). In Chicago, the average high-temperature in July slightly increases from an agreeable 70.5°F (21.4°C) in June to a warm 77.4°F (25.2°C). Weather in July »

Weather in August

The last month of the summer, August, is another warm month in Chicago, Illinois, with an average temperature ranging between max 77.5°F (25.3°C) and min 67.6°F (19.8°C). August is the warmest month, with an average high-temperature of 77.5°F (25.3°C) and an average low-temperature of 67.6°F (19.8°C). Weather in August »

Weather in September

September, the first month of the autumn in Chicago, is still a pleasant month, with temperature in the range of an average low of 61.2°F (16.2°C) and an average high of 71.1°F (21.7°C). In Chicago, the average high-temperature in September marginally drops from a moderately hot 77.5°F (25.3°C) in August to a pleasant 71.1°F (21.7°C). Weather in September »

Weather in October

October, like September, is a moderate autumn month in Chicago, Illinois, with temperature in the range of an average low of 48.9°F (9.4°C) and an average high of 59.5°F (15.3°C). In October, the average high-temperature drops from a pleasant 71.1°F (21.7°C) in September to a mild 59.5°F (15.3°C). Weather in October »

Weather in November

November, the last month of the autumn in Chicago, is another chilly month, with an average temperature fluctuating between 36.5°F (2.5°C) and 46°F (7.8°C). In Chicago, the average high-temperature in November decreases from a mild 59.5°F (15.3°C) in October to a chilly 46°F (7.8°C). Weather in November »

Weather in December

The first month of the winter, December, is also a wintry month in Chicago, Illinois, with an average temperature varying between 27.9°F (-2.3°C) and 35.8°F (2.1°C). In Chicago, Illinois, the average high-temperature in December decreases from a chilly 46°F (7.8°C) in November to a cold 35.8°F (2.1°C). Weather in December »
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FAQ

What is the coldest month in Chicago?

The coldest month in Chicago is January, 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 most humid month in Chicago?

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

How many days does it rain in Chicago?

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

When does it snow in Chicago?

Months with snowfall in Chicago, Illinois, are January through May, November and December.

How much does it snow in Chicago?

In Chicago, during the entire year, snow falls for 40.9 days and aggregates up to 13.9" (353mm) of snow.

What is the month with the least sunshine in Chicago?

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

When is the lowest UV index in Chicago?

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

When does it snow the most in Chicago?

February is the month with the most snowfall in Chicago. Snow falls for 9.9 days and accumulates 3.54" (90mm) of snow.

When is the ocean coldest in Chicago?

February is the month with the coldest seawater, with an average ocean temperature of 36.9°F (2.7°C).

When is Daylight Saving Time (DST) in Chicago?

On Sunday, March 12. 2023, at 2:00 am, Daylight Saving Time starts in Chicago, Illinois, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 5. 2023, at 2:00 am, and the time zone reverts from CDT to CST.

What is the rainiest month in Chicago?

June is the month with the most rainfall in Chicago, Illinois. Rain falls for 17.5 days and accumulates 4.88" (124mm) of precipitation.

When it does not snow in Chicago?

In Chicago, snow does not fall in June through October.

When are the longest days in Chicago?

June has the longest days of the year, with an average of 15h and 11min of daylight.

What are the months with the most sunshine in Chicago?

July and August, with an average of 10.6h of sunshine, are months with the most sunshine.

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

The months with the highest UV index are July and August, with an average maximum UV index of 6.

What is the warmest month in Chicago?

The warmest month is August, with an average high-temperature of 77.5°F (25.3°C) and an average low-temperature of 67.6°F (19.8°C).

What month is the ocean warmest in Chicago?

The month with the warmest seawater in Chicago, Illinois, is August, with an average ocean temperature of 73.9°F (23.3°C).

What is the least humid month in Chicago?

October is the least humid month in Chicago, with an average relative humidity of 73%.

What is the driest month in Chicago?

The month with the least rainfall is December, when the rain falls for 8.8 days and typically collects 1.65" (42mm) of precipitation.

What is the month with the shortest days in Chicago?

With an average of 9h and 11min of daylight, December has the shortest days of the year.

Average temperature
Chicago, IL

Average temperature - Chicago, IL

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).

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).

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Average pressure
Chicago, IL

Average pressure - Chicago, IL

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
Chicago, IL

Average wind speed - Chicago, IL

The windiest month (with the highest average wind speed) is January (12.5mph).
The calmest month (with the lowest average wind speed) is July (7.7mph).

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Average rainfall
Chicago, IL

Average rainfall - Chicago, IL

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

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Average rainfall days
Chicago, IL

Average rainfall days - Chicago, IL

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
Chicago, IL

Average snowfall - Chicago, IL

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

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Average snowfall days
Chicago, IL

Average snowfall days - Chicago, IL

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

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Average sea temperature
Chicago, IL

Average sea temperature - Chicago, IL

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).

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Average daylight / Average sunshine
Chicago, IL

Average daylight / Average sunshine - Chicago, IL

The month with the longest days is June (Average daylight: 15h and 11min).
The month with the shortest days is December (Average daylight: 9h and 11min).

The months with the most sunshine are July and August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

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Average sunshine days
Chicago, IL

Average sunshine days - Chicago, IL

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 visibility
Chicago, IL

Average visibility - Chicago, IL

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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