I raced two birds to 40 at g7 and g8, one foul the other fair. I don't have a basis for comparison with pre-nerf, but I did notice a big difference -- the fair one was noticeably more difficult to place well consistently because of the rain. The foul bird seems totally unaffected by any weather so he was much easier to level. Since leveling a foul g9 all the way to 50, I don't notice any difference if it's foul or fair weather.