Murk Avenue reports, after exhaustive research involving Lakers-SuperSonics games and Yo! MTV Raps airings, that the Good Day in question was January 20, 1992, 20 years ago a week ago. We will forever remember it.
Update (5:30 p.m.): Lot of things happening right now. At first we thought the blimp was grounded on the day in question. But it turned out, as reader Mike tweeted, "There are more than 1 goodyear blimps!" So the blimp in LA could still have been operational, although it had recently been repaired. More wrinkles: It may have rained on January 20, but it also might not have. We've called Goodyear to ask some questions, but they didn't answer the phone. They're spooked. Stay tuned.
Update (6 p.m.): Didn't rain in Compton!
Update (7 p.m.): Reader Keven points out that one can see the Goodyear blimp—and perhaps its lights—from the 405, which runs through southern LA. Cube doesn't say anything about the blimp being in the air.