The bug
The muffling effect that's supposed to happen to the rain sound effects when the rain is falling on a block above isn't determined by head position, i.e. when swimming or wading (on a non-full block like a slab or chest) in water during a rain storm with the player's head above the surface of the water the rain will sound as if it's hitting a ceiling above even thought it's falling right next to the player's head.
I can also sometimes get this same effect when having most of the player's body covered in solid blocks and just the player's head above, but not consistently.
Attachments
Comments 4
The way the "sound muffling" works appears to have been changed significantly since this bug has been reported, as such it's no longer applicable. The rain sound used to be either muffled or non-muffled. In current versions, the muffled and unmuffled sounds appear to be mixed somewhat.
It's possible that this bug still exists, however it can no longer be reproduced as easily, if that is the case.
You can reproduce this with soul sand as well. Attached some screenshots to clearify what's meant.