How do I know if I should say "Good afternoon or Good evening"?

Question

As a non-native speaker, how can I know? Thank you for your time.

Answer 1

Good Afternoon would be after 12 pm/noon and up to somewhere around 5pm, Evening, in my opinion, starts at 5:00 pm or 17:00 for those into the 24 hour clock. So after 5:00/17:00 you probably would start saying good evening.

Answer 2

By the time of day when you are making the statement.

Answer 3

"Good afternoon" is usually used from 12pm until 5pm then its "Good Evening"