December weather forecast
Prospect Heights, IL

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Weather in December

December, the first month of the winter in Prospect Heights, is also a wintry month, with temperature in the range of an average low of 25°F (-3.9°C) and an average high of 34.7°F (1.5°C).

Temperature

Welcoming December, Prospect Heights observes a shift in the average high-temperature, falling from November's frosty 45.5°F (7.5°C) to a cold 34.7°F (1.5°C). In Prospect Heights, the average low-temperature during the month of December is a subzero cold 25°F (-3.9°C).

Humidity

The average relative humidity in December in Prospect Heights, Illinois, is 80%.

Rainfall

The month with the least rainfall is December, when the rain falls for 8.5 days and typically collects 1.46" (37mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. In December, in Prospect Heights, Illinois, it is snowing for 9.5 days. Throughout December, 2.52" (64mm) of snow is accumulated. Throughout the year, there are 43.6 snowfall days, and 17.95" (456mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 12min of daylight.
On the first day of the month, sunrise is at 7:01 am and sunset at 4:20 pm. On the last day of December, in Prospect Heights, sunrise is at 7:19 am and sunset at 4:30 pm CST.

Sunshine

In December, the average sunshine is 4h.

UV index

The month with the lowest UV index in Prospect Heights is December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 1 translates into these guidelines:
Extended time in the sun generally does not harm most, but those with sensitive skin, infants, and children should always be protected. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
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Frequently asked questions

How cold is December in Prospect Heights?

The high-temperature in Prospect Heights, Illinois, during December is 34.7°F (1.5°C) and the low-temperature is 25°F (-3.9°C). In July, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which represents the influence of relative humidity on air temperature, is calculated to be 86°F (30°C).

What is the average humidity in December in Prospect Heights?

In Prospect Heights, Illinois, the average relative humidity in December is 80%.

What is the driest month in Prospect Heights?

The month with the least rainfall in Prospect Heights, Illinois, is December, when the rain falls for 8.5 days and typically collects 1.46" (37mm) of precipitation.

How many days does it rain in December in Prospect Heights?

In December, in Prospect Heights, the rain falls for 8.5 days. Throughout December, 1.46" (37mm) of precipitation is accumulated.

How much does it snow in Prospect Heights in December?

In December, in Prospect Heights, it is snowing for 9.5 days. Throughout December, 2.52" (64mm) of snow is accumulated.

What is the month with the shortest days in Prospect Heights?

With an average of 9h and 12min of daylight, December has the shortest days of the year in Prospect Heights, Illinois.

What is the average length of the day in December in Prospect Heights?

The average day length in December in Prospect Heights, Illinois, is 9h and 10min.

When are sunrise and sunset in December in Prospect Heights?

In December, on the first day of the month, sunrise is at 7:01 am and sunset at 4:20 pm. On the last day of the month, in Prospect Heights, Illinois, sunrise is at 7:19 am and sunset at 4:30 pm CST.

How many hours of sunshine does Prospect Heights have in December?

In December, the average sunshine duration in Prospect Heights is 4h.

What is the month with the lowest UV index in Prospect Heights?

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

What is the UV index intensity in December in Prospect Heights?

In Prospect Heights, Illinois, the average daily maximum UV index in December is 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to UV radiation.
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
Prospect Heights, IL

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

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (28.2°F).

  • Average low temperature in December: 25°F

The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (18°F).

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Average pressure in December
Prospect Heights, IL

Average pressure in December - Prospect Heights, IL
  • Average pressure in December: 30.09"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).

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Average wind speed in December
Prospect Heights, IL

Average wind speed in December - Prospect Heights, IL
  • Average wind speed in December: 9.7mph

The windiest month (with the highest average wind speed) is January (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).

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Average humidity in December
Prospect Heights, IL

Average humidity in December - Prospect Heights, IL
  • Average humidity in December: 80%

The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in December
Prospect Heights, IL

Average rainfall in December - Prospect Heights, IL
  • Average rainfall in December: 1.46"

The wettest month (with the highest rainfall) is May (3.9").
The driest month (with the least rainfall) is December (1.46").

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Average rainfall days in December
Prospect Heights, IL

Average rainfall days in December - Prospect Heights, IL
  • Average rainfall days in December: 8.5 days

The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is February (5.6 days).

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Average snowfall in December
Prospect Heights, IL

Average snowfall in December - Prospect Heights, IL
  • Average snowfall in December: 2.52"

The month with the highest snowfall is January (4.96").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in December
Prospect Heights, IL

Average snowfall days in December - Prospect Heights, IL
  • Average snowfall days in December: 9.5 days

The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in December /
Average sunshine in December
Prospect Heights, IL

Average daylight in December / Average sunshine in December - Prospect Heights, 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 0min

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

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Average sunshine days in December
Prospect Heights, IL

Average sunshine days in December - Prospect Heights, IL
  • Average sunshine days in December: 15.7 days

The month with the most sunshine days is November (16.3 days).
The month with the least sunshine days is June (10.7 days).

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Average UV index in December
Prospect Heights, IL

Average UV index in December - Prospect Heights, 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).

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Average cloud cover in December
Prospect Heights, IL

Average cloud cover in December - Prospect Heights, IL
  • Average cloud cover in December: 59

The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 29).

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Average visibility in December
Prospect Heights, IL

Average visibility in December - Prospect Heights, IL
  • Average visibility in December: 6mi

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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Prospect Heights, Illinois, USA

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