December weather forecastMason, IL
December
Weather in December
December, the first month of the winter in Mason, is also a wintry month, with an average temperature fluctuating between 29.3°F (-1.5°C) and 40.6°F (4.8°C).Temperature
Mason in December undergoes a mild reduction in the average high-temperature, shifting from November's cool 51.4°F (10.8°C) to an icy 40.6°F (4.8°C). Throughout December, an average low-temperature of 29.3°F (-1.5°C) is expected in Mason.Humidity
In December, the average relative humidity in Mason is 78%.Rainfall
In Mason, during December, the rain falls for 8.6 days and regularly aggregates up to 1.77" (45mm) of precipitation. In Mason, Illinois, 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 December, during 3.7 snowfall days, 1.81" (46mm) of snow is typically accumulated. In Mason, during the entire year, snow falls for 17.7 days and aggregates up to 6.73" (171mm) of snow.Daylight
With an average of 9h and 30min of daylight, December has the shortest days of the year in Mason, Illinois.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 7:13 am and sunset at 4:42 pm CST.
Sunshine
In Mason, the average sunshine in December is 4.6h.UV index
The months with the lowest UV index in Mason, Illinois, are January, February, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for the average person.Note: The daily maximum UV index of 2 in December interprets into the following advice:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Around midday, solar radiation is most harmful; hence, exposure should be limited. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
Average daylight in December /
Average sunshine in December
Mason, IL
- Average daylight in December: 9h and 30min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- 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).
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).
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).
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).
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).
