"Call at 5:00 pm."
Translation:E kelepona i ka hola ʻelima o ke ahiahi.
kakahiaka is from dawn to 10 am.
'awakea is from 10 am to 2 pm.
'auinala is from 2 pm to dusk.
'ahiahi is from dusk to dawn.
I do not know why this is 'ahiahi, but I am flagging it. Maybe dusk comes earlier in Hawai'i.
Great question. I do not know for sure but from my experience, these specific points on the clock seem to have become hard and fast rules.
Modernity has created a distinction between 1:59 and 2:00. I do not think it used to be that way, back in the day. A bit sad, if you ask me.