Is it weird to keep asserting that Summer Movie Season starts Memorial Day weekend, when Avengers: Endgame, the ultimate summer movie, and also the year's (the decade's! the century's!) biggest blockbuster, opened last month?
Maybe. Sure. Who cares?
"Summer movie" is a term, after all, that has taken on a negative connotation, as it tends to be deployed by those looking to sniffily dismiss the whole crop of films that come out in the months without an R. See also: "popcorn movies," "comic-book movies."