Answer:
There are several different greeting for different times of the day and situations.

ohaiyo gozaimasu - "good morning" until about noon.
konnichiwa - "good afternoon" until 5 pm or so.
konbanwa - "good evening" the rest of the day.

moshi moshi - "hello" on the telephone.

o genki desu ka - "how are you"

yokoso - "welcome" (to a place)
First answer by Clstaffprd. Last edit by Clstaffprd. Contributor trust: 6 [recommend contributor recommended]. Question popularity: 3 [recommend question].