It differs from person to person. There is no definite answer, and varies depending on when and how long the sun takes to go down where you are. The only one that is definite is that afternoon begins at 12pm (noon is 12pm, so afternoon is, well, "after" "noon", literally). In my opinion, the generally accepted timings are around: Afternoon - 12pm to 5-6pm Evening - 5-6pm to 7-8pm Night - 7-8pm (it overlaps a little with evening). When it ends depends on each person - some people consider 12 midnight to be the end of night and start of morning, but many people would instead consider night to last until around 3am.

Good morning is from midnight to noon. Good afternoon is from noon to sunset. Good evening is from sun set to bedtime. Good night is for bed time.

There are no exact times but usually morning is from sunrise to midday, afternoon is from midday to 5, evening is from 5 to sunset, and night is from sunset to sunrise. I hope that helps.