A tire rain protector made of a mushroom shaped polymer body having a reverse taper male thread formed thereon having a threadform with three varying geometric parameters. The thread thickness, thread height, and thread crest width all increase from the top of the tire rain protector body to the bottom of the body. These three features along with a thread that begins at the underside of the cap enable for a device that is easy to install and forms a secure tight seal on a tire. When installed, this dome-like device diverts rain from collecting into the concave liner (inner sidewalls) of a horizontally stacked tire.