December weather forecastVandalia, IL
December
Weather in December
December, the first month of the winter in Vandalia, is also a wintry month, with temperature in the range of an average high of 41°F (5°C) and an average low of 29.5°F (-1.4°C).Temperature
Stepping into December, Vandalia observes a temperature decline, with the average high falling from November's cool 51.8°F (11°C) to a cold 41°F (5°C). The average temperature drops to a subzero cold 29.5°F (-1.4°C) during the night in the month of December.Humidity
In Vandalia, the average relative humidity in December is 78%.Rainfall
In December, the rain falls for 9.7 days. Throughout December, 2.44" (62mm) of precipitation is accumulated. In Vandalia, Illinois, during the entire year, the rain falls for 164.1 days and collects up to 36.73" (933mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. December is the month with the most snowfall. Snow falls for 5.1 days and accumulates 2.4" (61mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 30min of daylight.On the first day of December, sunrise is at 6:56 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 4:44 pm CST.
Sunshine
In December, the average sunshine is 4.6h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum UV index of 2 during December translates into these guidelines:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Be alert to the fact! The reflection from snow can nearly double the UV radiation of the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Vandalia, IL
- Average high temperature in December: 41°F
The warmest month (with the highest average high temperature) is July (84°F).
The month with the lowest average high temperature is January (36°F).
- Average low temperature in December: 29.5°F
The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is January (23.4°F).
Average pressure in December
Vandalia, 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
Vandalia, IL
- Average wind speed in December: 9.3mph
The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).
Average humidity in December
Vandalia, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (81%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Vandalia, IL
- Average rainfall in December: 2.44"
The wettest month (with the highest rainfall) is June (4.57").
The driest month (with the least rainfall) is February (2.01").
Average rainfall days in December
Vandalia, IL
- Average rainfall days in December: 9.7 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (9.2 days).
Average snowfall in December
Vandalia, IL
- Average snowfall in December: 2.4"
The month with the highest snowfall is December (2.4").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Vandalia, IL
- Average snowfall days in December: 5.1 days
The month with the highest number of snowfall days is January (8.3 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
Vandalia, 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 18min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in December
Vandalia, IL
- Average sunshine days in December: 16.6 days
The month with the most sunshine days is October (17.2 days).
The month with the least sunshine days is July (8.6 days).
Average UV index in December
Vandalia, 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
Vandalia, 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, July and September (Cloud cover 30).
Average visibility in December
Vandalia, 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).
