Uh, cows, and just about every animal that can lay its head on or near its ass, sleep with their ass to the wind. Not because of the rain... the rain would actually be in it's eyes in that position. They do so because they then have their nose to the wind... and to the rain. That way, they can detect predators upwind and detect rain that may mask predetors. Once they detect a predator upwind, they are in position to spring into running in the opposite direction of predator approach.

I used to hunt Virginia White Tailed Deer to feed my family. This is one of the first lessons I was taught.