Anyone who rides a bike in the rain with his or her eyes open can see that the spray from the front tire sprays in a sort of wedge (actually more of a horn shape as the motion is a segment of a circle) starting from the back of the contact point.

Physics, folks. The tire from the top to the ground is moving Forward---- Spinning around the axle---and any spray from the front half of the tire (minimal because most spray is water picked up off the pavement) is going down and forward ... and all that "spray" is just raindrops hitting the tire (which is a pretty small target compared to your head and face.)

Spray from the back half of the tire, from the contact point back, is mostly road water flung by the tire and almost all goes goes back and up into the frame, or onto the feet.

Anyone who really rides in the rain doesn't need to be told.