A bit of trivia: even though the Winter Solstice isn't for another couple weeks, tomorrow will be the earliest sunset of the year (about 4:55 PM in San Francisco). That's because even though the days will keep getting shorter until December 22nd, sunrise will be getting later even faster.
(Calculated over at Express Tech's Sunrise and Sunset Calculator, which is only one I could find that includes seconds.)
Posted by bug to Science at December 6, 2006 5:30 PM