Sunrise and Sunset at the Winter Solstice
(Calculated for White Plains, NY)

Notice that
  • the earliest sunset occurs around December 8
  • the latest sunrise occurs around January 4
  • the shortest daylight period occurs on December 21
Between December 8 and the Winter Solstice on December 21, the sunrise is delayed more than the sunset, so the daylight period during that time continues to shorten. Between December 21 and January 8, the sunset is delayed more than the sunrise, and the daylight period begins to lengthen. After January 8, the sunset is still getting later, and the sunrise begins to occur earlier each day. Note, then, how quickly the days lengthen!

These changes are the result of the tilt of the earth's axis with relation to its orbital plane, and to the eccentricity of the earth's orbit. Both affect the equation of time.

Created on February 05, 2006 by Steve Kluge at Resources for GeoScience Education in North Salem, NY