To y'all semi-literate denizens of the Internet:
I know homophones (words that sound the same but have different meanings) can be tricky. But for crying out loud, "rain", "rein", and "reign" should not be.
RAIN: watery precipitation that falls from the sky. German cognate regen.
REIN: a strap used to control a horse. Latin cognate frenum.
REIGN: the period of rule by a king, emperor, or powerful principle (e.g. "reign of terror") Latin cognate regnum.
Perhaps it's the fact that hardly anybody outside Mongolia rides horses on the job anymore that causes this silly confusion.