The Weathering Continent is based on the novel series from Sei Takekawa which had illustrations by Mutsumi Inomata that ran for twenty-eight volumes between 1990 and 2006.
The Weathering Continent arrived in the summer of 1992 but was part of a triple bill with the second Heroic Legend of Arslan film and the second Silent Mobius film.
One of the things that I loved about anime in the 80s and 90s was that the whole double-feature thing for anime films worked well.
Often the films that were paired together matched in some ways but we also had others that were mismatched.