December weather forecast
Lemont, IL

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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).

Temperature

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). Throughout December nights, Lemont registers an average low-temperature of 24.6°F (-4.1°C).

Humidity

In Lemont, the average relative humidity in December is 81%.

Rainfall

The month with the least rainfall is December, when the rain falls for 7.1 days and typically collects 1.06" (27mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In Lemont, in December, during 9.7 snowfall days, 1.89" (48mm) of snow is typically accumulated. In Lemont, during the entire year, snow falls for 44.4 days and aggregates up to 11.93" (303mm) of snow.

Daylight

December has the shortest days of the year in Lemont, with an average of 9h and 12min of daylight.
On the first day of the month, sunrise is at 7:00 am and sunset at 4:22 pm. On the last day of December, sunrise is at 7:18 am and sunset at 4:31 pm CST.

Sunshine

In Lemont, the average sunshine in December is 4.1h.

UV index

December is the month with the lowest UV index in Lemont, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for the average person.
Note: The daily maximum UV index of 1 in December interprets into the following advice:
Apart from children, who require continuous protection, most can endure sun exposure for up to an hour without experiencing burns. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.

Frequently asked questions

How cold is December?

During December, Lemont experiences an average high-temperature of 34.7°F (1.5°C) and a low-temperature of 24.6°F (-4.1°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, in July is appraised at 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 81%.

What is the driest month in Lemont?

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

How many days does it rain in December?

In Lemont, during December, the rain falls for 7.1 days and regularly aggregates up to 1.06" (27mm) of precipitation.

How much does it snow in December?

In Lemont, in December, during 9.7 snowfall days, 1.89" (48mm) of snow is typically accumulated.

What is the month with the shortest days?

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

What is the average length of the day in December?

The average day length in December is 9h and 13min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:00 am and sunset at 4:22 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:31 pm CST.

How many hours of sunshine does Lemont have in December?

In Lemont, the average sunshine duration in December is 4.1h.

What is the month with the lowest UV index in Lemont?

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

How high is the UV index in December?

In December, the average daily maximum UV index is 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Lemont, IL

Average temperature in December - Lemont, IL
  • Average high temperature in December: 34.7°F

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).

  • Average low temperature in December: 24.6°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 in December
Lemont, IL

Average pressure in December - Lemont, IL
  • Average pressure in December: 30.1"Hg

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 in December
Lemont, IL

Average wind speed in December - Lemont, IL
  • Average wind speed in December: 9mph

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 in December
Lemont, IL

Average humidity in December - Lemont, IL
  • Average humidity in December: 81%

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

Average rainfall in December
Lemont, IL

Average rainfall in December - Lemont, IL
  • Average rainfall in December: 1.06"

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 in December
Lemont, IL

Average rainfall days in December - Lemont, IL
  • Average rainfall days in December: 7.1 days

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 in December
Lemont, IL

Average snowfall in December - Lemont, IL
  • Average snowfall in December: 1.89"

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 in December
Lemont, IL

Average snowfall days in December - Lemont, IL
  • Average snowfall days in December: 9.7 days

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 in December /
Average sunshine in December
Lemont, IL

Average daylight in December / Average sunshine in December - Lemont, IL
  • Average daylight in December: 9h and 1min

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).

  • Average sunshine in December: 4h and 1min

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 in December
Lemont, IL

Average sunshine days in December - Lemont, IL
  • Average sunshine days in December: 16.2 days

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 UV index in December
Lemont, IL

Average UV index in December - Lemont, IL
  • Average UV index in December: 1

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in December
Lemont, IL

Average cloud cover in December - Lemont, IL
  • Average cloud cover in December: 58

The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 31).

Average visibility in December
Lemont, IL

Average visibility in December - Lemont, IL
  • Average visibility in December: 6mi

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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