The tally, and what still leaves room for doubt
The Sun enters Sagittarius at two hundred and forty degrees of ecliptic longitude, and across those one hundred and six years the crossing always happened before midday on the twenty third. Sagittarius is therefore the right answer for a noon birth in any of them.
The doubt that remains is narrow but genuine. In years where the ingress ran late, a birth in the first hours of 23 November in a time zone well behind Greenwich can still fall on the Scorpio side. That is the case the widget above exists for. It takes your year, your hour and your birthplace, works out the single moment they describe, and reports how many hours that moment stood from the boundary.
Sign lengths and the drifting boundary
The Sun does not spend equal time in every sign. The Earth is closest to the Sun in early January and moving fastest then, so the signs around that point take about twenty nine and a half days, while Cancer and Gemini near the July aphelion take about thirty one and a half. Scorpio and Sagittarius sit on the shortening side of that curve, which keeps their boundaries a little tighter than the summer ones.
Tighter is not fixed. The tropical year runs about a quarter of a day longer than the calendar year, so each ingress falls roughly six hours later on the clock than the year before until a leap day pulls it back by something like eighteen hours. Follow the Scorpio to Sagittarius boundary across a decade and it covers about a day and a half of calendar time. That is the whole reason a printed range cannot settle a date this close to the line.
The ingress is one instant, the local date is not
Only one thing changes from country to country, and it is the clock rather than the Sun. When Sagittarius begins at 03:00 UTC on 22 November, that same instant is ten in the evening on the twenty first in New York and seven in the evening in Los Angeles. An American birth record can therefore carry a date that appears to contradict a European table while describing exactly the same sky.
Getting that conversion wrong is the most frequent cause of a sun sign being reported incorrectly, more common by far than any genuine disagreement about method. It also has a definite answer, which is why it is worth resolving rather than arguing about.
Scorpio, Sagittarius, and what does not change either way
Scorpio is fixed water ruled by Mars traditionally and by Pluto in modern practice, read as concentrated, guarded and thorough. Sagittarius is mutable fire ruled by Jupiter, read as expansive, candid and restless. The old scheme puts them next to each other as the night houses of Mars and Jupiter, and they share a reputation for bluntness, though Scorpio is blunt about what it has worked out and Sagittarius about what it has just thought of.
Neither sign leaks into the other. The Sun holds one degree of longitude at any moment and that degree lies inside a single sign, so a birth a quarter of an hour before the change is entirely Scorpio and one a quarter of an hour after is entirely Sagittarius. The cusp is a name for details that were never established, not a third condition. And if the answer is not the one you grew up with, keep it in scale: the Sun is a single placement, and the Moon, the Ascendant and the rest of the chart are unmoved by which side of this line you arrived on.
Questions people ask about this
Is 23 November Scorpio or Sagittarius?
Sagittarius. At noon it has been Sagittarius in every year from 1930 to 2035, because the Sun enters the sign on 21 or 22 November in practice. A birth in the small hours in the Americas is the only case worth checking closely.
Why did a magazine tell me I was Scorpio?
Because magazine ranges are rounded to fixed dates and copied from one another. The real boundary moves across 21 and 22 November depending on the year, and a table that runs Scorpio to the twenty third is simply rounding generously.
Am I on the Scorpio Sagittarius cusp?
No. At any instant the Sun is at one ecliptic longitude, and that longitude sits inside one sign with nothing shared across the boundary. The cusp label points at missing birth details rather than a blended sign.
Do I need my birth time?
Not to settle the sun sign on this date in most cases, since the ingress has passed by the time the day starts. You do need it for the Ascendant and the houses, so it is worth finding for other reasons.
Why are some signs longer than others?
Because the Earth's orbit is not a circle. Near the closest approach to the Sun in early January the Earth moves fastest and the Sun crosses a sign in about twenty nine and a half days, while near the July aphelion it takes about thirty one and a half.
Does being born on a boundary date affect the rest of my chart?
No. Only the Sun is in question, and only for a few hours either side of one instant. The Moon, the Ascendant and every planet are calculated from the same birth moment and are unaffected by the sign boundary.