I read a study of classical piano students. The best ones, who were expected to become pros, all practiced in the morning; and there was some practice at other hours -- the same pattern, as far as I can remember. The good but less elite students also tended to work in the morning, but with more variance and less total practice. (This was one of those studies about the 10,000-hour rule and deliberate practice -- I think there were some refs to studies of other fields showing similar practices.)
Everyone needs to find what works best for themselves, but I'm pretty sure now I was just being macho when I thought I did best at night.
Actually the article showed ALL the writers wrote in the morning (well the 9 of 10 that mentioned when they wrote). It also said that many of them could/would write at other times as well but they ALL started in the morning.
