December weather forecast
Mason, IL

Weather in December

December, the first month of the winter in Mason, is also a wintry month, with an average temperature fluctuating between 40.6°F (4.8°C) and 29.3°F (-1.5°C).

Temperature

In December, the average high-temperature decreases from a cool 51.4°F (10.8°C) in November to a cold 40.6°F (4.8°C). In December, in Mason, the average low-temperature is 29.3°F (-1.5°C).

Humidity

In December, the average relative humidity is 78%.

Rainfall

In December, the rain falls for 8.6 days. Throughout December, 1.77" (45mm) of precipitation is accumulated. In Mason, during the entire year, the rain falls for 141.3 days and collects up to 26.77" (680mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall in Mason. In Mason, in December, snow falls for 3.7 days, with typically accumulated 1.81" (46mm) of snow. In Mason, Illinois, during the entire year, snow falls for 17.7 days and aggregates up to 6.73" (171mm) of snow.

Daylight

The month with the shortest days is December, with an average of 9h and 29min of daylight.
On the first day of the month, sunrise is at 6:54 am and sunset at 4:32 pm. On the last day of December, in Mason, sunrise is at 7:12 am and sunset at 4:41 pm CST.

Sunshine

In December, the average sunshine is 4.6h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Mason, Illinois. A UV Index value of 2, and less, symbolizes a minimal health hazard from unsafe exposure to UV radiation for the average person.
Note: The average daily UV index of 2 in December transform into the following instructions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
[Resources]

FAQ

What is the temperature in December in Mason?

In December, the average high-temperature is 40.6°F (4.8°C), and the average low-temperature is 29.3°F (-1.5°C). The average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, in August is computed to be 89.6°F (32°C).

What is the average humidity in December in Mason?

In December, the average relative humidity is 78%.

How much does it rain in Mason in December?

In Mason, Illinois, during December, the rain falls for 8.6 days and regularly aggregates up to 1.77" (45mm) of precipitation.

How many days does it snow in December in Mason?

In December, it is snowing for 3.7 days. Throughout December, 1.81" (46mm) of snow is accumulated.

What is the month with the shortest days in Mason?

With an average of 9h and 29min of daylight, December has the shortest days of the year in Mason, Illinois.

What is the average length of the day in December in Mason?

The average day length in December is 9h and 29min.

When is the sunrise / sunset in December in Mason?

On the first day of December in Mason, sunrise is at 6:54 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 4:41 pm CST.

How long on average sun shines in December in Mason?

In December, the average sunshine duration is 4.6h.

When is the lowest UV index in Mason?

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2.

What is the UV index intensity in December in Mason?

In Mason, Illinois, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents 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
Mason, IL

Average temperature in December - Mason, IL
  • Average high temperature in December: 40.6°F

The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (35.6°F).

  • Average low temperature in December: 29.3°F

The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).

[Resources]

Average pressure in December
Mason, IL

Average pressure in December - Mason, IL
  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

[Resources]

Average wind speed in December
Mason, IL

Average wind speed in December - Mason, IL
  • Average wind speed in December: 9.4mph

The windiest months (with the highest average wind speed) are January and February (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

[Resources]

Average humidity in December
Mason, IL

Average humidity in December - Mason, IL
  • Average humidity in December: 78%

The months with the highest relative humidity are July and August (81%).
The month with the lowest relative humidity is October (71%).

[Resources]

Average rainfall in December
Mason, IL

Average rainfall in December - Mason, IL
  • Average rainfall in December: 1.77"

The wettest month (with the highest rainfall) is April (3.35").
The driest month (with the least rainfall) is February (1.38").

[Resources]

Average rainfall days in December
Mason, IL

Average rainfall days in December - Mason, IL
  • Average rainfall days in December: 8.6 days

The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (7.3 days).

[Resources]

Average snowfall in December
Mason, IL

Average snowfall in December - Mason, IL
  • Average snowfall in December: 1.81"

The month with the highest snowfall is January (2.01").
The months with the least snowfall are April, May, June, July, August, September and October (0").

[Resources]

Average snowfall days in December
Mason, IL

Average snowfall days in December - Mason, IL
  • Average snowfall days in December: 3.7 days

The month with the highest number of snowfall days is January (5.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

[Resources]

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

Average daylight in December / Average sunshine in December - Mason, IL
  • Average daylight in December: 9h and 29min

The month with the longest days is June (Average daylight: 14h and 52min).
The month with the shortest days is December (Average daylight: 9h and 29min).

  • Average sunshine in December: 4h and 36min

The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).

[Resources]

Average sunshine days in December
Mason, IL

Average sunshine days in December - Mason, IL
  • Average sunshine days in December: 19.5 days

The month with the most sunshine days is December (19.5 days).
The month with the least sunshine days is May (10.8 days).

[Resources]

Average UV index in December
Mason, IL

Average UV index in December - Mason, IL
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

[Resources]

Average cloud cover in December
Mason, IL

Average cloud cover in December - Mason, IL
  • Average cloud cover in December: 51

The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are June and September (Cloud cover 29).

[Resources]

Average visibility in December
Mason, IL

Average visibility in December - Mason, 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).

[Resources]

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location
* you will be automatically redirected to the weather forecast for your location