early sunset

Today, plus or minus a day, is the earliest sunset of the year locally. (No, it's not the solstice. Pico-explanation: because the solar day isn't always the same length.) The first explanation of this I heard, and that I kind of grokked, was an earlier version of this essay by Larry Denenberg (which I just found in email from 1997). The Naval Observatory also has a short explanation.

By "plus or minus a day", I mean that I haven't found any place that gives astronomical times down to the second.