BTW: I did not post a pic of my pedals, but they ARE cheapos, so I guess you are right. Mine are Odyssey Twisted PC platforms for which I paid $17. If THESE are sufficient in the rain, I'd say ANY pinned platform should give RandomEncounter what he needs.
Also, in an earlier post, I mentioned that clips (cages, etc) have an advantage in that they keep your feet from slipping off the pedals when you are "digging in," which sounds like a contradiction of what I am saying about platforms. I was referring to how you can push extra hard on the pedals, or even pull up, when you are climbing a rough hill and not lose your footing. This has nothing to do with riding in the rain.