Winter begins! The name "winter" comes from an old Germanic word meaning "time of water" and refers to the seasonal precipitation. The winter solstice—the moment when the sun's apparent path is farthest south from the equator—is used to officially mark winter's beginning. In the Northern Hemisphere, winter begins on the "shortest day" of the year, which most frequently falls on December 21, but occasionally occurs on December 22. Winter lasts until the vernal, or spring, equinox--equal night--around March 20, thus marking the beginning of spring when day and night are equal in length. (from the Library of Congress)
Winter begins at midnight....hard to believe.