This past Sunday's 8am-11am ride was 51-55F light to moderate rain. As a top I only wore just a long sleeve wool jersey (EWR) and was warm. The jersey was damp (expect under arms and sides which never got direct rain and stayed dry) but I felt fine. Other riders said: hey you need to get real rain gear. I said why if I am warm? I have a rain jacket and I just sweat and get nasty under it.