The time at which your brain works the best is between 10:00 AM to 2:00 PM.
Then again your brain works the best in the evenings between the hours of 4:00 PM to 10:00 PM.
When I was studying at home for college I would do my best learning between the hours of 8:00 PM to 10:00 PM and even sometimes in the middle of the night.
When the world was quiet and I was up in the middle of the night I could do my best learning during the middle of the night hours.
It was peaceful and relaxing and so I would sleep most of the day and then in the middle of the night I would do my studying while my family was asleep.
Your brain is also pretty active at night when sleeping as your brain is processing information, storing information and thinking about things.
Some people suffer from Insomnia at night because they are thinking about things and worrying and their brain won't shut off.