Add greetings based on specific time

I would like to train the model to return back greetings based on specific time in the day or year.
For example in the morning, answer “Good morning” and the answer, in the evening “Good evening” and the answer.

I understand GPT doesn’t have notion of time, but if needed I may pass date and time to achieve it. How I can implement it using prompt or API?

Thank you

I would code that directly and prepend it to whatever you want the AI to respond with.