Many of us consider ourselves either a morning person or a night owl—times when we feel more productive, awake, and think better. Not all types of thinking tasks, though, fit in with what we consider the optimal time of day for us. The Creativity Post points out that creativity happens when you least expect it.
Our internal clocks dictate when our brainpower is at its peak. Those are the times when we can really concentrate and complete tasks that require working memory, which The Creativity Post calls "our flexible mental scratch pad." For morning types, this means working on demanding cognitive tasks (e.g., solving analytical problems) is best done early in the day. For night owls, later in the day is better.