The space between the pins, plates and rollers is not fully filled with lube. Water moves everywhere inuding uphill. Water in and of itself is not an issue it is how the lube deals with the water. Some thick lubes will blend the water into a oil/water foam of sorts. This causes the films to fail. Some of the dry type films are largely unaffected by water. The chain gets wet it dries out and the lube is still there clinging to the metal.

Even using a crevace tool tool and a wet dry vacuum to suck the water out of a mounted chain works. I also sometimes wash the bike and blow everything dry with a leaf vac or compressed air. Both work well to dry the chain out and prepare it for a re oiling. The key is making room for new lube and letting it soak in deep

I ride year round in some real crap weather. I only break out the rain bike for salty road conditions. I wash salt off as often as weather conditions permit