Originally Posted by CPcyclist
Remember the bike needs lube.
That's probably the worst part about riding in the rain, there's nothing known to man that will stay on a chain through persistent rain. Wax-based lubes are hopeless, I find oil-based will work somewhat, the greasier and goopier the better, like BoeShield or Phil's tenacious. And just keep putting more on at every opportunity.
It's a good idea to have lights in the rain too.