I'd have a hard time documenting this ... but I was taught the "45 degree rule." That is, an overhang's protection was imagined as an area of 45 degrees from the lip to the wall. Items within this zone were "damp," while items closer to the lip were "wet" locations.
This would be a more conservative practice than the NEMA-3R rain test, which presumes a rain falling at only a 15 degree angle.
Personally, I use this for deciding "to bubble or not." I put at least flap covers on anything that is exposed, and use 'Bell" type boxes where the boxes are exposed.
Why? My reason has nothing to do with weather.Rather, I am weary of evicting wasps and spiders from device boxes.
