When can I use "have a good day"? [closed]

While I agree with most of what WS2 says, they have not answered your specific question, which is about whether Have a good day is limited to the morning. And the answer is No, it is not. If you use it, you can use it any time of the day, though probably not when it is getting dark.

And contra WS2, who has assumed you are using the phrase with a stranger as a conventional farewell, there are contexts where I suspect even WS2 would use it with no qualms: when waving friends or family off for a day out somewhere.

Since time of day differs, depending on who and where you are talking to. Being mindful of the time is important when talking long distance. Have a good day is a positive and hopeful sentence and can be used during the day until sundown. After that you could say did you have a good day? This then Opens up lines of communication about what happened during day. This is just my humble opinion.