As I've been studying birth charts more, I've noticed that it becomes clear what time of the day a person is born based on what house/which of the four quadrants the Sun is in.
This only works with whole sign houses. If you'd like to test this out yourself, I recommend setting the house system to "whole sign" when calculating your chart.
When I mention the "horizon line", I'm referring to the line that separates the top six houses (houses 7 through 12) and the bottom six houses (houses 1 through 6).
I casted a few "Hypothetical Person" charts for July 1, 2000 to demonstrate this.
The sunrise time for a specific date would more often than not put the sun on the 1st house, because the sun glyph in the chart is literally rising above the horizon line, heading into the 12th house (and so on) as the day progresses. Anytime the sun is in houses 1 through 3, the sun is rising away from it's lowest point (the nadir or the Imum Coeli/IC), and becoming visible on the eastern horizon. The sunrise time on July 1, 2000 was 5:46 a.m.
The solar noon time (or otherwise known as high noon or midday) for a specific date would more often than not put the sun on the 10th house because the sun has reached the highest point in the sky, fully visible from our point of view on earth, therefore the sun glyph is also at its highest point within the chart. Anytime the sun is in houses 10 through 12, the sun is rising away from the eastern horizon, and culminating towards its highest point (the meridian or the Midheaven/MC). The solar noon time on July 1, 2000 was 1:12 p.m.
The sunset time for a specific date would more often than not put the sun on the 7th house, because the sun glyph in the chart is setting below the horizon line, moving into the 6th house (and so on) as the night progresses. Anytime the sun is in houses 7 through 9, the sun is falling away from it's highest point, and it loses visibility as it approaches the western horizon. The sunset time on July 1, 2000 was 8:37 p.m.
At midnight, the sun is almost always in the 4th house, because the Sun has fully set below the horizon line and it cannot be seen. Midnight, however, isn't always 12:00 a.m. on the dot, just like solar noon isn't always 12:00 p.m. on the dot; as shown in the first chart, midnight on July 1, 2000 was 1:11 a.m. Anytime the sun is in houses 4 through 6, the sun is falling away from the western horizon, and anti-culminating towards complete invisibility at the nadir.
This can be applied for any day, depending of course on whether or not the sun is changing signs on said day (hence why I said "almost always" and "more often than not"); the sunrise time for July 16, 2000 puts the sun on the 2nd house because the sun had changed signs from Gemini to Cancer. However, on July 17, 2000, at the time of sunrise, the sun was back on the 1st house.
The sunrise, sunset, and solar noon times for the dates mentioned above were found through using this website.
