Saturday is the winter solstice, the shortest day of the year in the Northern Hemisphere. Benjamin Liss / dpa/AFP via Getty Images Saturday is the winter solstice in the Northern Hemisphere.
Followers of Druidism, celebrate the pagan solstice festival at the site each year. (Photo by JUSTIN TALLIS / AFP) (Photo by JUSTIN TALLIS/AFP via Getty Images) Why is Dec. 21 the winter solstice?