I think the danger posed by rain to leather saddles is wayyyy overstated. Unless you drop the thing in a lake, or leave it out overnight in a thunderstorm, rain is not going to hurt it. Even then there's not really much danger unless you ride on them while they're still wet. I don't think I've heard of a single instance of somebody leaving their bike in the rain, only to find out that their saddle self destructed simply because of that.