2 of the last 4 years we've been hit with a good bit of rain during my 5 day seasons here in WI and I was able to score on both. It didn't start raining until 9 on the third day(Friday) of the '05 season and I told myself I'd hang in until I was soaked. Did some stalking to within 200 yards along a fence row and was able to call in a good sized jake. No trophy but I went home with a bird when no one else did that weekend.
This past year, it rained all night and the birds didn't get off the roost until it slowed up around 8am in the morning. I sat with a buddy of mine who happens to be the landowner and the owner of a very nice Double Bull blind we sat in. Had some coffee and watched the birds for over an hour pick their way thru a field towards us until the big daddy got within shooting disance. Laid him out at 42 yards (according to the rangefinder). As bad as I wanted to start calling when they entered the field, we never made a peep the whole time they were out there. I wouldn't do it again without the aid of a blind, but you can take them with patience and a lucky setup.