Despite several recommendations for the Brooks fabric-covered neoprene saddles (e.g. C17) as being very weather-resistant, the discussion turns back to Brooks leather saddles (e.g. B17), which are only somewhat weather-resistant.

My experience is that the most weather-resistant (and for my ass the most comfortable) leather saddle is made by Selle Anatomica in their "watershed" leather. I stopped using my SA on my commuting bike only because my heft eventually bends the rails, but I still love it on my road bike.