Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
The transition into December indicates a reduction in the average high-temperature, down to a chilly 43.2°F (6.2°C) from November's fresh 52.7°F (11.5°C). December's nights observe an average temperature of 30.9°F (-0.6°C).Humidity
In December, the average relative humidity in Mount Vernon is 78%.Rainfall
In Mount Vernon, during December, the rain falls for 8.9 days and regularly aggregates up to 2.01" (51mm) of precipitation. Throughout the year, in Mount Vernon, there are 145.8 rainfall days, and 29.13" (740mm) of precipitation is accumulated.Snowfall
January through April, November and December are months with snowfall in Mount Vernon. In Mount Vernon, in December, snow falls for 2.9 days, with typically accumulated 1.06" (27mm) of snow. Throughout the year, in Mount Vernon, there are 15.4 snowfall days, and 5.87" (149mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 36min of daylight.On the first day of December, sunrise is at 6:54 am and sunset at 4:35 pm. On the last day of the month, sunrise is at 7:12 am and sunset at 4:45 pm CST.
Sunshine
In December, the average sunshine is 4.8h.UV index
The months with the lowest UV index are January, November and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the average person.Note: A maximum UV index of 2 in December translates into the following recommendations:
Most people face no serious problems with extended sun exposure, but those with fair skin, infants, and children always need protection. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December in Mount Vernon?
What is the average humidity in December in Mount Vernon?
How many days does it rain in December in Mount Vernon?
How much does it snow in Mount Vernon in December?
What is the month with the shortest days in Mount Vernon?
What is the average length of the day in December in Mount Vernon?
What time are sunrise and sunset in December in Mount Vernon?
How long on average sun shines in December in Mount Vernon?
What is the month with the lowest UV index in Mount Vernon?
What is the UV index reading in December in Mount Vernon?
Average temperature in December
Mount Vernon, IL
- Average high temperature in December: 43.2°F
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in December: 30.9°F
The month with the highest average low temperature is July (67.8°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).
Average pressure in December
Mount Vernon, IL
- Average pressure in December: 30.14"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
Mount Vernon, IL
- Average wind speed in December: 9.1mph
The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.9mph).
Average humidity in December
Mount Vernon, IL
- Average humidity in December: 78%
The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Mount Vernon, IL
- Average rainfall in December: 2.01"
The wettest month (with the highest rainfall) is April (3.78").
The driest month (with the least rainfall) is September (1.61").
Average rainfall days in December
Mount Vernon, IL
- Average rainfall days in December: 8.9 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is January (7.5 days).
Average snowfall in December
Mount Vernon, IL
- Average snowfall in December: 1.06"
The month with the highest snowfall is February (1.73").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Mount Vernon, IL
- Average snowfall days in December: 2.9 days
The month with the highest number of snowfall days is January (4.8 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
Mount Vernon, IL
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 4h and 5min
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 30min).
Average sunshine days in December
Mount Vernon, IL
- Average sunshine days in December: 19.9 days
The month with the most sunshine days is October (20.3 days).
The month with the least sunshine days is May (11.3 days).
Average UV index in December
Mount Vernon, IL
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, November and December (UV index 2).
Average cloud cover in December
Mount Vernon, IL
- Average cloud cover in December: 49
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is June (Cloud cover 27).
Average visibility in December
Mount Vernon, 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).
Mount Vernon, Illinois, USA
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