Though it may appear otherwise, winter will only officially start December 21 at 3:39 p.m. Each year has two solstices which mark both the longest and shortest days of the year.
Summer solstice in June is the beginning of summer and the shortening of daylight in the Northern hemisphere; winter solstice, six months later in December, is the beginning of winter and the lengthening of days in the Northern hemisphere.
In some ancient and even modern cultures the solstices come with festivals and celebrations.
Early Christian communities transformed some of the practices into excepted parts of Christmas celebrations.
“Let us love winter, for it is the spring of genius.”-- Pietro Aretino.