Weather mods are loaded last in the Load Order, and normally add or modify Climate and ImageSpace records, and then overwrite worldspace records (such as WastelandNV, or in Wasted Return of LOD case, MegatonWorld) to change the CNAM and INAM records on them (Climate and ImageSpace respectively) (ParadiseFalls worldspace is not affected in Wasted Return of LOD by this since it has no Climate nor ImageSpace).

Unfortunately, doing so also overwrites the other records in the worldspace, including what Wasted Return of LOD mod scopes to change: its flags. Specifically, Wasted Return of LOD just enables the "use LOD data" flag in MegatonWorld and ParadiseFalls worldspaces. It is that simple, forreal.

Since Wasted Return of LOD mod contains an .esm, it will always load before weather mods (which are always loaded last) and will inevitably conflict with them, by essentially being overwritten. Climates will be applied but the worldspace will not use LOD data.

Weather mods would require a patch to solve the conflict. Like this modpage's patch.

That's why.