The January 16th issue of TIME magazine has a major section on "How to Sharpen Your Mind."
One of the key articles explores the best times of day for both "Morning People" and "Night Owls" to create, problem solve, rejuvinate and rest. I've re-worked the graphics presented in TIME for this post.
For the Morning Person
TIME says, for the early riser, "creativity generally peaks early in the wake cycle before distractions can impede the brain's imaginative focus."
Check out For the Night Owls