There is a guy I see every day from the train on Elephant and Castle station platform who has a folding bike and the most clothing I've ever seen on a cyclist, including massive waterproof trousers. He has been wearing the same gear since January. I'm betting he is a terrible cyclist.
He is, last time I saw him he was in a thick black jacket (I think he mostly wears black) despite being over 20c.
Being totally overdressed for the weather seems to be a common trait in terrible cyclists.