While it may seem like trivia, it (causes huge headaches for software developers / is taken advantage of by high-speed traders / triggered the 2003 Northeast Blackout / has to be corrected for by GPS satellites / is now recognized as a major cause of World War I).
This is the second comic using Facts in the title.
Randall presents what appears to be a generator of 156,000 facts [20 x 13 x (8 + 6 x 7) x 12] (780,000 if including the title text) about calendars, most of which are false or have little meaning.[citation needed] The facts are seeded by a mishmash of common tidbits about the time of year.
The formula for each generated fact goes as follows: "Did you know that [a recurring event] [occurs in an unusual manner] because of [phenomena or political decisions]? Apparently [wild card statement]." The title text adds on as follows: "While it may seem like trivia, it [real-life consequence]."
This is the fifth time that Randall has referred to the phenomenon of a supermoon, which he typically makes fun of, most prominently in 1394: Superm*n.
The title text continues the chart with supposed real-life consequences of the trivia in the comic.
There are multiple online generators of Calendar 'facts' using this formula here and here.
All 156 000 possible combinations can be found here, lovingly assembled by hand (or rather, by a Python script) for your entertainment. A random fact generator (including title text), written in Python, can be found here.