Evan:
Rain has had alot -- actually, almost everything -- to do with how soft the course is playing.
It can absolutely be made to play F&F, and in fact played much faster in '04, when the winning score was -8.
I'm virtually certain it was playing very F&F in late May of this year, as two regular GCA contributers played two courses in the same state at the same latitude and said they played as fast and firm as they'd ever seen. But that was the result of a very cool and dry early spring in these parts. Since June, Wisconsin has been pretty much deluged with a major storm or two a week. (Sheboygan, WI averages 6.2 inches of rain in June and July; this year, it received 12.5 inches of rain in those two months). WStraits got more rain the Monday and Wednesday before the tournament started, and it rained again last night before today's play.
Fast and firm, with four days of wind of the sort that popped up Friday afternoon when the weather was moving through, and WS would play incredibly tough at 7,500 yards -- I'm not sure you'd see many players under par. But this soft and green, without much wind, and it's playing as something of a target golf course, with most high scores on holes resulting from poor decisions or poor execution, as opposed to conditions and weather.