December starts on Saturday, meaing it's the beginning of Meteorological Winter (December, January & February, as opposed to Astronomical Winter, which begins on December 21st).
December is a month in which temperatures continue to cool. On December 1st, the average high is 46 degrees, and the average low is 28 degrees. At the end of the month, New Year's Eve average high is 38 degrees, and the average low is 21 degrees. We also average 4.8 inches of snow in mid-Missouri for December and 2.44 inches of precipitation.
December is also our "darkest" month of the year, in regards to the amount of daylight we receive. On December 1st, we'll see 9 hours and 41 minutes of daylight, and on December 31st, we'll see 9 hours and 31 minutes of daylight.