flametitan
Explorer
The only adventure that is really out of place is Princes of the Apocalypse which states within it that it takes place in 1491. This pretty much sets it after all of the other released adventures up to Storm Kings Thunder. Storm Kings Thunder contains an encounter with cultists from the elemental evil air cult which suggests that they are in the early days of their plans.
That might explain why it feels like PotA's integration to SKT feels more fleshed out than the others, if they're the closest to each other chronologically.