In most cases, our in-wall and in-ceiling speakers can weather the elements perfectly well.
Anything you put into the care of Mother Nature, however, will unavoidably be affected in one way or another. There will be some discoloration over time, but it's nothing a fresh layer of paint can't cure.
Damage will mostly affect the color and the housing, but the inner workings should not fail, since the great majority of speakers are made of synthetic materials. Locations with marine air will certainly accelerate the discoloration.
Speakers will work fine in overhangs, wrap-around/covered porches, garages, and more. However, try not to listen to the speakers in sub freezing temperatures. They will be brittle and may crack.