Warm rain is nice. Cool rain is refreshing. Cold rain is miserable. In any event, a long full front fender that keeps spray off your toes is really nice, and a rear fender to keep the spray off your back is also nice.

I've been riding with a rain cape for the last couple of years, and it's really nice and cold rain. It's a little hot in warm rain. And it's really nice in heavy rain regardless of the temperature. You don't stay completely dry, you may perspire a little, but you're not getting pelted by the rain.