Climate and monthly weather forecast
Lake Forest, IL

Weather in January

January, the same as December, in Lake Forest, Illinois, is a freezing cold winter month, with temperature in the range of an average low of 18.9°F (-7.3°C) and an average high of 28.6°F (-1.9°C). With an average high-temperature of 28.6°F (-1.9°C) and an average low-temperature of 18.9°F (-7.3°C), January is the coldest month. Weather in January »

Weather in February

February, the last month of the winter in Lake Forest, is also a subzero cold month, with an average temperature varying between 21.6°F (-5.8°C) and 31.3°F (-0.4°C). In February, the average high-temperature is practically the same as in January - a still freezing cold 31.3°F (-0.4°C). Weather in February »

Weather in March

The first month of the spring, March, is a cold month in Lake Forest, Illinois, with an average temperature varying between 31.5°F (-0.3°C) and 41.5°F (5.3°C). In March, the average high-temperature increases from a freezing cold 31.3°F (-0.4°C) in February to a cold 41.5°F (5.3°C). Weather in March »

Weather in April

April in Lake Forest, Illinois, is a fresh spring month, with an average temperature fluctuating between 39.7°F (4.3°C) and 50.9°F (10.5°C). In April, the average high-temperature rises from a wintry 41.5°F (5.3°C) in March to a fresh 50.9°F (10.5°C). Weather in April »

Weather in May

The last month of the spring, May, is a comfortable month in Lake Forest, Illinois, with an average temperature varying between 49.6°F (9.8°C) and 61.2°F (16.2°C). In May, the average high-temperature increases from a cool 50.9°F (10.5°C) in April to a comfortable 61.2°F (16.2°C). Weather in May »

Weather in June

The first month of the summer, June, is a pleasant month in Lake Forest, Illinois, with an average temperature ranging between max 71.1°F (21.7°C) and min 59.4°F (15.2°C). In Lake Forest, the average high-temperature in June increases from a comfortable 61.2°F (16.2°C) in May to a pleasant 71.1°F (21.7°C). Weather in June »

Weather in July

July is a warm summer month in Lake Forest, Illinois, with an average temperature fluctuating between 77.7°F (25.4°C) and 66.7°F (19.3°C). With an average high-temperature of 77.7°F (25.4°C) and an average low-temperature of 66.7°F (19.3°C), July is the warmest month. Weather in July »

Weather in August

August, the last month of the summer in Lake Forest, is another warm month, with an average temperature fluctuating between 66.7°F (19.3°C) and 77.5°F (25.3°C). In August, the average high-temperature is essentially the same as in July - a still moderately hot 77.5°F (25.3°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a pleasant month in Lake Forest, Illinois, with an average temperature fluctuating between 71.2°F (21.8°C) and 60.1°F (15.6°C). In Lake Forest, the average high-temperature in September slightly decreases from a warm 77.5°F (25.3°C) in August to an agreeable 71.2°F (21.8°C). Weather in September »

Weather in October

October, like September, is another mild autumn month in Lake Forest, Illinois, with an average temperature fluctuating between 58.6°F (14.8°C) and 47.7°F (8.7°C). In October, the average high-temperature decreases from an agreeable 71.2°F (21.8°C) in September to a moderate 58.6°F (14.8°C). Weather in October »

Weather in November

The last month of the autumn, November, is another chilly month in Lake Forest, Illinois, with temperature in the range of an average low of 35.1°F (1.7°C) and an average high of 45.5°F (7.5°C). In November, the average high-temperature drops from a moderate 58.6°F (14.8°C) in October to a chilly 45.5°F (7.5°C). Weather in November »

Weather in December

The first month of the winter, December, is still a cold month in Lake Forest, Illinois, with an average temperature fluctuating between 26.2°F (-3.2°C) and 34.5°F (1.4°C). In December, the average high-temperature decreases from a frosty 45.5°F (7.5°C) in November to a cold 34.5°F (1.4°C). Weather in December »
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FAQ

What is the coldest month in Lake Forest?

With an average high-temperature of 28.6°F (-1.9°C) and an average low-temperature of 18.9°F (-7.3°C), January is the coldest month.

What are the most humid months in Lake Forest?

The months with the highest humidity are January and February, with an average relative humidity of 82%.

How much does it rain in Lake Forest?

In Lake Forest, Illinois, during the entire year, the rain falls for 154.1 days and collects up to 30.24" (768mm) of precipitation.

When does it snow in Lake Forest?

Months with snowfall in Lake Forest, Illinois, are January through April, October through December.

What is the snowiest month in Lake Forest?

January is the month with the most snowfall. Snow falls for 11.9 days and accumulates 4.13" (105mm) of snow.

How many days does it snow in Lake Forest?

Throughout the year, there are 42.9 snowfall days, and 13.82" (351mm) of snow is accumulated.

What is the month with the least sunshine in Lake Forest?

With an average of 3.8h of sunshine, January has the least sunshine of the year in Lake Forest.

When is Daylight Saving Time (DST) in Lake Forest?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 6. 2022, at 2:00 am, and the time zone reverts from CDT to CST.

What is the wettest month in Lake Forest?

The months with the most rainfall in Lake Forest, Illinois, are May and June, with an average 3.82" (97mm) of precipitation.

When it does not snow in Lake Forest?

May through September are months without snowfall in Lake Forest.

When are the longest days in Lake Forest?

The month with the longest days in Lake Forest is June, with an average of 15h and 13min of daylight.

What are the months with the highest UV index in Lake Forest?

June through August, with an average maximum UV index of 6, are months with the highest UV index in Lake Forest, Illinois.

What is the warmest month in Lake Forest?

With an average high-temperature of 77.7°F (25.4°C) and an average low-temperature of 66.7°F (19.3°C), July is the warmest month.

What month has the most sunshine in Lake Forest?

August has the most sunshine of the year in Lake Forest, with an average of 10.7h of sunshine.

What is the least humid month in Lake Forest?

The least humid month is October, with an average relative humidity of 73%.

What is the driest month in Lake Forest?

The month with the least rainfall in Lake Forest is December, when the rain falls for 8.6 days and typically collects 1.3" (33mm) of precipitation.

What is the month with the shortest days in Lake Forest?

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

What is the month with the lowest UV index in Lake Forest?

With an average maximum UV index of 1, December is the month with the lowest UV index in Lake Forest, Illinois.

Average temperature
Lake Forest, IL

Average temperature - Lake Forest, IL

The warmest month (with the highest average high temperature) is July (77.7°F).
The month with the lowest average high temperature is January (28.6°F).

The months with the highest average low temperature are July and August (66.7°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

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Average pressure
Lake Forest, IL

Average pressure - Lake Forest, IL

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed
Lake Forest, IL

Average wind speed - Lake Forest, IL

The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).

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Average humidity
Lake Forest, IL

Average humidity - Lake Forest, IL

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

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Average rainfall
Lake Forest, IL

Average rainfall - Lake Forest, IL

The wettest months (with the highest rainfall) are May and June (3.82").
The driest month (with the least rainfall) is December (1.3").

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Average rainfall days
Lake Forest, IL

Average rainfall days - Lake Forest, IL

The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (5.9 days).

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Average snowfall
Lake Forest, IL

Average snowfall - Lake Forest, IL

The month with the highest snowfall is January (4.13").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days
Lake Forest, IL

Average snowfall days - Lake Forest, IL

The month with the highest number of snowfall days is January (11.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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Average daylight / Average sunshine
Lake Forest, IL

Average daylight / Average sunshine - Lake Forest, IL

The month with the longest days is June (Average daylight: 15h and 13min).
The month with the shortest days is December (Average daylight: 9h and 9min).

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

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Average sunshine days
Lake Forest, IL

Average sunshine days - Lake Forest, IL

The month with the most sunshine days is December (15.3 days).
The month with the least sunshine days is April (10.8 days).

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Average visibility
Lake Forest, IL

Average visibility - Lake Forest, 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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