Diurnal: of or during the day.
Nocturnal: done, occurring, or active at night.
Matutinal: of or occurring in the morning.
Vespertine: relating to, occurring, or active in the evening.
Crepuscular: of, resembling, or relating to twilight.
Out of the five words, I’ve only regularly seen nocturnal being used. However once I read crepuscular somewhere and wrote it down in my notebook. Now I forget where I read it and what the context is. I am not a crepuscular person who’s only active during the twilight periods, but I love dawn and dusk. I think many people are like me. So crepuscular is a nice word to me, although it doesn’t sound like English–probably a Greek or Latin word.
Long ago, I worked in a hospital for a year and talked to two nurses regularly since we shared the dorm room for staff members. They complained about the night shifts constantly. According to them, night shifts are very unsuitable for healthy human existence since they can’t sleep well during the day no matter how tired and sleepy they are. I wouldn’t know this unless I really talk with people who have night shifts. Later I read something that says nocturnal activities disrupt the circadian rhythm of the body, putting people in a constant jet lag mode, rather damaging to the health.