A boundary inside the date
Taking noon in each year from 1930 to 2035, the solar longitude on this date runs from about 9.1 to about 10.5 degrees of Scorpio. The line between the first face and the second sits at exactly ten. The range therefore contains the line, and the answer changes from one year to another.
Early years in the span tend to come out in the first face and late ones in the second, because within each four year leap cycle the position climbs and then resets. Any page that states a single decan for this birthday has picked one without saying so. The honest answer is that it depends, and the widget above resolves it from your own year, hour and birthplace. It also reports how far the position sits from the nearest boundary, which is the figure that says whether the answer is comfortable or marginal.
The mechanism behind the split
The Sun covers a bit under one degree a day, so a ten degree face takes about ten days to cross and the boundary moment lands at a specific hour rather than at midnight. When the range for a calendar date straddles a face line, births a few hours apart on the same day can fall on opposite sides.
The reason the range is as narrow as it is comes from the leap year rule, which keeps the calendar aligned with the orbit. The Sun arrives about six hours later each ordinary year, then a leap day pulls it back roughly a day. Over the modern era the total spread on a given date stays inside a degree and a half, and here that small spread happens to sit across a boundary.
What changes when the face changes
The first face of Scorpio answers to Mars in the Chaldean order and to Scorpio itself in the triplicity count, so both routes lead back to Mars, or to Pluto if you use the modern ruler. The second face is different on both counts. Chaldean order puts the Sun there, and the triplicity scheme assigns it to Pisces.
The readings that follow are correspondingly different. A face that repeats the sign is read as the sign undiluted, with nothing else in the mix to shift the emphasis. A solar face inside a water sign, with Pisces in the background, is read as something warmer and less guarded than Scorpio's reputation suggests. Neither reading is a prediction, and neither applies until you know which side of ten your own Sun landed on.
Everything else the date leaves open
Even with the decan settled, a birth date fixes very little. The Moon changes sign every two to three days, so it is narrowed to a couple of options and often crosses a boundary during the day itself. Mercury may be in Scorpio, Libra or Sagittarius depending on the year.
The Ascendant is undetermined by the date in any form. It depends on the birthplace and the clock time, and it moves through the whole zodiac in twenty four hours, which is roughly one sign every two hours. This is why the sun sign is the least individual thing a chart contains, and why a page about a birthday can only ever be about the parts the date genuinely fixes.
Questions people ask about this
Which decan is 2 November?
It depends on the year. The noon Sun runs from about 9.1 to 10.5 degrees across 1930 to 2035, and the face boundary sits at ten, so earlier years tend to give the first face and later ones the second.
Is the sign itself in doubt?
Not at all. Scorpio began around the twenty third of October and runs to about the twenty second of November, so this date is well inside it in every year.
Why does the year change the answer?
Because the calendar and the orbit are only approximately matched. The Sun arrives about six hours later each ordinary year and a leap day resets it, so the position on a fixed date oscillates by more than a degree.
Could the hour of birth matter here?
Yes, in a year where the noon position is very close to ten degrees. The Sun moves about a degree a day, so a birth in the early morning and one late at night can fall on opposite sides.
What are the two rulers involved?
Mars for the first face by the Chaldean order, with Scorpio itself by the triplicity count. The second face goes to the Sun in the Chaldean sequence and to Pisces in the triplicity one.
Does the decan affect my sun sign reading?
It refines it rather than changing it. The sign stays Scorpio either way, and the face adds a second planetary attribution that the sign label on its own does not carry.