I have attended the Sisters Outdoor Quilt show many times, and was there last year when it rained (briefly). I was in the tent and helped bring in the quilts that were hanging where the rain might reach them. I was impressed by how well all the quilts were handled and how quickly everything came down when it started raining. I have also attended the Quilts in the Garden outdoor show in Corvallis, Oregon. I might not want to enter an all-white silk whole cloth (LOL) but would be honored to display any of my quilts in those outdoor shows. I don't think a single day of sunshine would be that detrimental, and rain is just water. The worst that might happen, IMHO, is theft, and that can happen at any show.