Read the long blurb at the front of this post Mark, it explains what the idea is about this game. The obvious answer is that you don't know the wind speed in mph for a single shot, but.. with experience you can judge whether the wind is stronger for a shot than it was for the previous shot. So the exact speed doesn't matter - you learn from previous targets, and you learn from the zero range too. (that's why there's a zero range in the game) As Simon says - 'Experience' - but the premise of this game is that part of the secret of shooting in the wind is experience, and part of it is ballistics. The experience part you have to get by shooting, the ballistics part you can learn sat in front of your computer.