Well, there's the key ... define "weatherproof."
No need to run to Webster's
The earlier UL standard, and the current NEMA standards, do it for us. In short, anything that passes the test qualifies. In the case of NEMA 3-R (raintight), all this means is that the enclosure did not collect an 'objectionable' amount of water during the defined rain test, and that live parts were not submerged.
On second thought ... I stand corrected. The standards define 'raintight,' and not 'weatherproof.' What is the NEMA designation for 'weatherproof?'
This puts things in an interesting paradox: An open receptacle pointed 'down' will pass, while adding a cover to a downward pointing receptacle might actually cause a test failure by trapping water within.
I certainly hope we don't require 'damp' locations to use Bell boxes, etc. If we do, EVERY crawl space in America is in violation. After all, NM-B is not allowed in damp location, and crawl spaces are by definition damp- as any home inspector
(whom I blame for THAT code change).
Bath fixture? How does the area next to a shower differ from the area immediately under a roof's eave? Sounds like an appropriate choice to me.