I have a PVC Jacket that I use ina pinch, but I prefure my convertable jacket to carry instead. Either way you drench yourself from the inside, but not as bad with the convertable Maybe try scoring one of those tyvek jackets that they hand out to every one before a cool morning start on a marathon or some charity rides. I have found that with bike wear you get what you pay for. Best of luck on you search.
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I miss my 4.8lb base weight as a ground dweller. But I sure don't miss the ground.