I have a lightweight, neon-butt-ugly rain jacket for medium rains. In summer around here, I'll sweat wearing it, so gotta keep the pace down. In my years of backpacking and biking experience, there is no magic bullet for staying dry in hot weather when its raining. Either you go jersey only and get drenched, or you wear rain gear and get sweat-drenched. So, I back off the pace a tad and wear my rain jacket and it works pretty well. I don't bother with the legs. Shorts get a little wet, no big deal. I don't cover the helmet with anything either. Maybe a little water gets in, not too much.