Climate and monthly weather forecast
Lemont, IL

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Weather in January

January, the same as December, in Lemont, Illinois, is a freezing cold winter month, with an average temperature varying between 17.1°F (-8.3°C) and 28.8°F (-1.8°C). January, with its high-temperature average of 28.8°F (-1.8°C) and a low-temperature average of 17.1°F (-8.3°C), is the coldest month. Weather in January »

Weather in February

The last month of the winter, February, is an icy month in Lemont, Illinois, with an average temperature varying between 32.5°F (0.3°C) and 19.9°F (-6.7°C). Lemont's February showcases an average high-temperature of an icy 32.5°F (0.3°C), hardly distinct from January's 28.8°F (-1.8°C). Weather in February »

Weather in March

March, the first month of the spring in Lemont, is a chilly month, with an average temperature ranging between max 45.7°F (7.6°C) and min 32°F (0°C). Lemont's March weather shows an increase in high-temperatures, moving from February's icy 32.5°F (0.3°C) to a frosty 45.7°F (7.6°C). Weather in March »

Weather in April

April is a refreshing spring month in Lemont, Illinois, with an average temperature varying between 57°F (13.9°C) and 41°F (5°C). The arrival of April brings an increase in high-temperatures, moving from a frosty 45.7°F (7.6°C) in March to a moderate 57°F (13.9°C). Weather in April »

Weather in May

May, the last month of the spring in Lemont, is an agreeable month, with an average temperature varying between 69.4°F (20.8°C) and 52.3°F (11.3°C). May sees a rise in the average high-temperature, climbing from a mild 57°F (13.9°C) in April to an agreeable 69.4°F (20.8°C). Weather in May »

Weather in June

June, the first month of the summer in Lemont, is a warm month, with an average temperature ranging between max 78.6°F (25.9°C) and min 61.3°F (16.3°C). With the onset of June, Lemont experiences a temperature shift, with the average high-temperature moving from an agreeable 69.4°F (20.8°C) in May to a moderately hot 78.6°F (25.9°C). Weather in June »

Weather in July

July, like June, in Lemont, Illinois, is another warm summer month, with an average temperature fluctuating between 65.7°F (18.7°C) and 81.9°F (27.7°C). July is the warmest month of the year, registering average temperatures as high as 81.9°F (27.7°C) and as low as 65.7°F (18.7°C). The heat index in July is appraised at a tropical 87.8°F (31°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Lemont, Illinois, with temperature in the range of an average high of 80.2°F (26.8°C) and an average low of 63.9°F (17.7°C). Lemont experiences a transition to a still moderately hot 80.2°F (26.8°C) in average high-temperatures with the arrival of August, not greatly differing from July's 81.9°F (27.7°C). Weather in August »

Weather in September

September, the first month of the autumn in Lemont, is still a warm month, with an average temperature fluctuating between 57.4°F (14.1°C) and 74.3°F (23.5°C). As September commences, the average high-temperature subtly reduces, transitioning from 80.2°F (26.8°C) in August to a still moderately hot 74.3°F (23.5°C). Weather in September »

Weather in October

October, like September, is another refreshing autumn month in Lemont, Illinois, with an average temperature fluctuating between 45.5°F (7.5°C) and 60.6°F (15.9°C). Transition from September to October is accompanied by a temperature drop, with average high-temperatures decreasing from a warm 74.3°F (23.5°C) to a mild 60.6°F (15.9°C). Weather in October »

Weather in November

November, the last month of the autumn in Lemont, is also a frosty month, with an average temperature fluctuating between 33.4°F (0.8°C) and 46.6°F (8.1°C). Onset of November comes with a temperature decline, the average high falling from a mild 60.6°F (15.9°C) in October to a chilly 46.6°F (8.1°C). Weather in November »

Weather in December

The first month of the winter, December, is also a wintry month in Lemont, Illinois, with an average temperature fluctuating between 24.6°F (-4.1°C) and 34.7°F (1.5°C). A moderate decline in the average high-temperature is seen during December, decreasing from a chilly 46.6°F (8.1°C) in November to an icy 34.7°F (1.5°C). Weather in December »

Frequently asked questions

What is the coldest time of year in Lemont?

January, with its high-temperature average of 28.8°F (-1.8°C) and a low-temperature average of 17.1°F (-8.3°C), is the coldest month.

What is the most humid month?

The months with the highest humidity are January and February, with an average relative humidity of 83%.

How many days does it rain?

Throughout the year, there are 145.4 rainfall days, and 22.83" (580mm) of precipitation is accumulated.

When does it snow?

January through May, October through December are months with snowfall.

When does it snow the most?

January is the month with the most snowfall. Snow falls for 12.1 days and accumulates 3.11" (79mm) of snow.

How many days does it snow?

Throughout the year, there are 44.4 snowfall days, and 11.93" (303mm) of snow is accumulated.

What is the month with the least sunshine?

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

When is Daylight Saving Time (DST) in Lemont?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Lemont, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the rainiest month?

The month with the most rainfall is May, when the rain falls for 16.4 days and typically aggregates up to 2.83" (72mm) of precipitation.

When it does not snow?

In Lemont, snow does not fall in June through September.

When are the longest days?

The month with the longest days is June, with an average of 15h and 12min of daylight.

What are the months with the highest UV index?

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

What time of the year is the hottest?

The warmest period tends to be July, when average temperatures fluctuate between a high of 81.9°F (27.7°C) and a low of 65.7°F (18.7°C).

What are the months with the most sunshine in Lemont?

The months with the most sunshine are July and August, with an average of 9.9h of sunshine.

What is the least humid month?

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

What is the driest month?

December is the month with the least rainfall. Rain falls for 7.1 days and accumulates 1.06" (27mm) of precipitation.

What is the month with the shortest days in Lemont?

December has the shortest days of the year, with an average of 9h and 12min of daylight.

What is the month with the lowest UV index?

December is the month with the lowest UV index, with an average maximum UV index of 1.

Average temperature
Lemont, IL

Average temperature - Lemont, IL

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (28.8°F).

The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).

Average pressure
Lemont, IL

Average pressure - Lemont, 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).

Average wind speed
Lemont, IL

Average wind speed - Lemont, IL

The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).

Average humidity
Lemont, IL

Average humidity - Lemont, IL

The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is October (73%).

Average rainfall
Lemont, IL

Average rainfall - Lemont, IL

The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is December (1.06").

Average rainfall days
Lemont, IL

Average rainfall days - Lemont, IL

The month with the highest number of rainy days is July (18.1 days).
The month with the least rainy days is February (4.9 days).

Average snowfall
Lemont, IL

Average snowfall - Lemont, IL

The month with the highest snowfall is January (3.11").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days
Lemont, IL

Average snowfall days - Lemont, IL

The month with the highest number of snowfall days is January (12.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight / Average sunshine
Lemont, IL

Average daylight / Average sunshine - Lemont, IL

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

The months with the most sunshine are July and August (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

Average sunshine days
Lemont, IL

Average sunshine days - Lemont, IL

The month with the most sunshine days is November (18.4 days).
The month with the least sunshine days is July (9.3 days).

Average visibility
Lemont, IL

Average visibility - Lemont, IL

The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and February (5mi).

Lemont, Illinois, USA

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