I can see why you think it’s stupid, why give a name to something that’s not observable and entirely based on our arbitrarily chosen delimiters on calendar months. Sort of like calling the 3rd full moon in a month a “blue moon”, or really any of the various named full moons.
Whoops, I got that definition of a blue moon wrong. Can’t have 3 in a month. Meant to say “2nd”
Yep, and apparently some almanac just made it up in the 30s.
Isn’t pretty much everything from almanacs just made up? My religious parents used to swear by the farmer’s almanac. Then whenever it was wrong, they were like, “it’s not always right, but it usually is”