The winter solstice occurs exactly when the Earth's axial tilt is farthest away from the sun at its maximum of 23° 26'. Though the winter solstice lasts only a moment in time, the term is also a turning point to midwinter or the first day of winter to refer to the day on which it occurs. More evident to those in high latitudes, this occurs on the shortest day and longest night, when the sun's daily maximum position in the sky is the lowest.
The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days. Depending on the shift of the calendar, the winter solstice occurs on December 21 or 22 each year in the Northern Hemisphere, and June 20 or 21 in the Southern Hemisphere. The 2010 winter solstice (summer solstice in the southern hemisphere) occurred on December 21, at 23:38 UTC. This is 11:38 pm Western European Time (WET) or 6:38 pm Eastern Standard Time (EST).
Worldwide, interpretation of the event has varied from culture to culture, but most cultures have held a recognition of rebirth, involving holidays, festivals, gatherings, rituals or other celebrations around that time.