The only way to really understand the problem of very large scale phenonema is to use statistics.
Imagine, for the sake of clarity, a human shaped as a cube, 1 metre on each side, standing in a flat field, basically a "physics" or "maths" type of infinite flat surface.
Imagine further that raindrops are falling at a constant rate
of 1 metre per second ,1metre apart in all directions.
Each cubic metre will then contain 1 raindrop and 1 drop will land on the "top" surface of the cube man each second.
It then makes no difference if he is stationary or moving about at any velocity, the number of drops striking his "head" will be precisely the same.
If moving he will run into more drops than if still but he will leave behind by dint of movement the exact same number of drops which would have hit him if he hadn't be moving.