Honey, this one's for you:

Not a morning person? Take solace — new research suggests that "night owls" are more likely to be creative thinkers.

Scientists can't yet fully explain why evening types appear to be more creative, but they suggest it could be an adaptation to living outside of the norm....

Scientists scored each [group of Morning, Intermediate, and Evening people as they] completed activit[ies based] on originality, elaboration, fluidity and flexibility factors. Evening types aced each test based on these criteria, while morning and intermediate type people struggled to get scores over 50. - Night Owls Are More Creative, Says Study

Via dangerousmeta.

This is an odd result, but if the reporting is accurate, a fairly strong one. I don't think I buy the tentative explanation at all, though:

"Being in a situation which diverges from conventional habit — nocturnal types often experience this situation — may encourage the development of a non-conventional spirit and of the ability to find alternative and original solutions," lead author Marina Giampietro and colleague G.M. Cavallera wrote

I can't speak for everybody, but my "non-conventional spirit" was fully developed when I was still stuck in the early morning paradigm imposed by my entirely conventional school. If there is a link, I don't think it's cause and effect between "creativity" and "night owl"; it's going to be a cause C underlying both.

The journal is for-pay and at $30 an article I'm not likely to buy the real study when it comes out in February, so no primary-source love here. Another article will also appear in that journal issue:

We administered measures of fluid and crystallized intelligence to Morning- and Evening-type adolescents who were tested either during a morning session or an afternoon session, at times chosen to reflect the limits of the average school day schedule. For the fluid intelligence measures, there was a synchrony effect, with better performance at times that matched individuals’ preferences. A composite measure of the subtests used (block design, digit span, and vocabulary) computed to a 6 point difference in IQ estimates. We also assessed the behavioral adjustment of these participants and found heightened levels of maladaptive behavior for Evening-type adolescents. Adolescents tested at their nonoptimal times of day and adolescents who are Evening-types appear to be at risk for poor academic performance and Evening-types appear to be at risk for behavioral adjustment problems. - Time of day, intellectual performance, and behavioral problems in Morning versus Evening type adolescents: Is there a synchrony effect?