Beyond staying indoors, that is…
I’m pretty much convinced there is no such thing as a “breathable waterproof” outer shell, though perhaps there are miracle products out there I haven’t been apprised of. For my money there’s no substitute for an impermeable layer — which, of course, locks in body heat and perspiration and ends up making you as wet on the inside as you’d have been with no protection at all.
I’m leaning closer to getting a cheap waterproof poncho. It lets air in from the sides and keeps water off the places where it concentrates — the head and shoulders. It can also double as a shelter in a pinch. I realize this is not exactly a bolt of insight to those of you who’ve already gone this route, but I like to toss out something for the beginners now and again.
I’d like to hear how the rest of you stay dry when the rains come.