December weather forecast
Pontiac, IL

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Weather in December

December, the first month of the winter in Pontiac, is also an icy month, with an average temperature fluctuating between 25.9°F (-3.4°C) and 36.5°F (2.5°C).

Temperature

The move into December indicates a reduction in the average high-temperature, down from November's frosty 47.5°F (8.6°C) to a wintry 36.5°F (2.5°C). Pontiac throughout December, experiences an average nighttime temperature of 25.9°F (-3.4°C).

Humidity

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

Rainfall

In Pontiac, in December, it is raining for 6.2 days, with typically 0.75" (19mm) of accumulated precipitation. In Pontiac, during the entire year, the rain falls for 125.3 days and collects up to 15.71" (399mm) of precipitation.

Snowfall

January through April, October through December are months with snowfall. In December, it is snowing for 6.3 days. Throughout December, 0.94" (24mm) of snow is accumulated. In Pontiac, during the entire year, snow falls for 30.6 days and aggregates up to 6.93" (176mm) of snow.

Daylight

December has the shortest days of the year, with an average of 9h and 18min of daylight.
On the first day of the month, sunrise is at 7:00 am and sunset at 4:27 pm. On the last day of December, sunrise is at 7:18 am and sunset at 4:36 pm CST.

Sunshine

In Pontiac, the average sunshine in December is 4.3h.

UV index

The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily high UV index of 1 during December translates into the following recommendations:
Extended exposure to the sun should always be avoided by children, infants, and those with sensitive skin. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Updated: Jun 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in December?

The high-temperature during December is 36.5°F (2.5°C) and the low-temperature is 25.9°F (-3.4°C). In July, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which factors the actual air temperature with the relative humidity, is calculated to be 87.8°F (31°C).

What is the average humidity in December?

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

How many days does it rain in December?

In Pontiac, in December, it is raining for 6.2 days, with typically 0.75" (19mm) of accumulated precipitation.

How much does it snow in December?

In December, it is snowing for 6.3 days. Throughout December, 0.94" (24mm) of snow is accumulated.

What is the month with the shortest days?

With an average of 9h and 18min of daylight, December has the shortest days of the year.

How many hours of daylight does Pontiac have in December?

The average day length in December is 9h and 18min.

What time are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:00 am and sunset at 4:27 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 4:36 pm CST.

How long on average sun shines in December?

The average sunshine duration in December is 4.3h.

When is the lowest UV index?

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

How high is the UV index in December?

The average daily maximum UV index in December is 1. A UV Index value of 2, and less, symbolizes a minimal hazard to health 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
Pontiac, IL

Average temperature in December - Pontiac, IL
  • Average high temperature in December: 36.5°F

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (30.2°F).

  • Average low temperature in December: 25.9°F

The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (18.5°F).

Average pressure in December
Pontiac, IL

Average pressure in December - Pontiac, IL
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in December
Pontiac, IL

Average wind speed in December - Pontiac, IL
  • Average wind speed in December: 10.1mph

The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).

Average humidity in December
Pontiac, IL

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

The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (71%).

Average rainfall in December
Pontiac, IL

Average rainfall in December - Pontiac, IL
  • Average rainfall in December: 0.75"

The wettest month (with the highest rainfall) is May (2.44").
The driest months (with the least rainfall) are January and February (0.71").

Average rainfall days in December
Pontiac, IL

Average rainfall days in December - Pontiac, IL
  • Average rainfall days in December: 6.2 days

The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is January (4.3 days).

Average snowfall in December
Pontiac, IL

Average snowfall in December - Pontiac, IL
  • Average snowfall in December: 0.94"

The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Pontiac, IL

Average snowfall days in December - Pontiac, IL
  • Average snowfall days in December: 6.3 days

The month with the highest number of snowfall days is January (10.2 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Pontiac, IL

Average daylight in December / Average sunshine in December - Pontiac, IL
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 4h and 2min

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

Average sunshine days in December
Pontiac, IL

Average sunshine days in December - Pontiac, IL
  • Average sunshine days in December: 19.3 days

The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is July (11.3 days).

Average UV index in December
Pontiac, IL

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

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

Average cloud cover in December
Pontiac, IL

Average cloud cover in December - Pontiac, IL
  • Average cloud cover in December: 55

The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 32).

Average visibility in December
Pontiac, IL

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

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

Pontiac, Illinois, USA

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