Studies In Scarlet
Before we get to what this might mean for the Justice League movie, we must note one more red-sky mention. In the first episode of The CW's The Flash, viewers saw a 2024 headline not only proclaiming the Flash's disappearance in a "crisis," but observing that the "red skies" had also vanished. While this was clearly an Easter egg alluding to Barry Allen's death in Crisis #8, it alerted viewers that the series aspired to be faithful to the comics' Crisis. Put simply, the Flash producers knew that red skies equaled Crisis, and wanted to let viewers know that they knew.
This specificity might also help fans know what to prepare for. Flash's red-sky reference was part of a larger Crisis allusion, but so far the Justice League trailers haven't made that connection. While this could be part of Warner Brothers' spoiler management, we're less inclined to think Justice League is setting up its own Crisis.
For one thing, the Arrowverse now has enough parallel Earths that it would be surprising if it didn't do a version of Crisis On Infinite Earths. (See also this month's "Crisis On Earth-X" crossover.) For another, we know that Justice League's villains come from Apokolips, which (thanks to external factors) didn't have much to do with Crisis On Infinite Earths. Instead, it seems more likely that Justice League's color palette is intended to follow similar choices in Man of Steel (where Krypton's red sun colored its sky accordingly) and the "Knightmare" sequence in Batman v. Superman. Granted, they could all be building towards a Crisis of some sort, but we don't think it's imminent.
Perhaps it boils down to correlation versus causation. Although red skies were an integral part of Crisis On Infinite Earths, once that seminal story had ended, so did their special significance. As the years went by, red skies became less and less associated with Crisis specifically. Red-sky callbacks in Infinite Crisis and Flash were simply part of larger COIE homages, and didn't do much for the trope otherwise. Now the red-sky crossover stands largely on its own, as the big-event equivalent of a participation trophy.
Even so, those red skies do give Justice League's trailers that extra bit of creeping dread. Here's hoping that their presence in the film doesn't inspire any eye-rolling from jaded comics fans: "Not this again!?"
Do you think Justice League's red skies herald a Crisis? Let us know in the comments!