Early morning (early morning): 5:00-7:00
Morning: 6:00-8:00
Morning: 6:00- 12:00
At noon: 12:00 or so.
Afternoon: 12:00- 18:00
Evening (dusk): 17:00 or so.
Evening: 18:00-6:00.
Midnight: around 24 o'clock.
Some moments vary with the seasons (sunrise and sunset).