4:30 refers to the time of day that is four hours and thirty minutes past midnight or noon, depending on the context. In a 12-hour clock format, this can be either 4:30 AM or 4:30 PM.
If you’re looking at a 24-hour clock, 4:30 is simply 16:30. This time can often be associated with either morning activities, typically around wake-up time for some, or evening events, as it is shortly before dinner time in many cultures.