The position first
At noon in every year from 1930 to 2035, the Sun on this date stood between roughly two and three and a half degrees of Scorpio. The ingress happens around 23 October and shifts by up to a day and a half between years, so by this date the crossing is complete in all of them with a margin of two degrees or more.
That figure holds still for a mechanical reason. A common year is about a quarter of a day short of the orbit, so the Sun arrives some six hours later each year on the clock, and the leap day every fourth February pulls the reckoning back by close to a full day. The creep and the correction nearly cancel, leaving a swing of a little over a degree.
Mars, the older answer
In the traditional scheme every sign but the two lit by the Sun and Moon shares a ruler with one other sign, and Mars takes Aries and Scorpio. The pairing is old, predates the telescope entirely, and gives Scorpio a ruler that is visible to the naked eye and moves at a rate anyone can observe.
On this account the sign is read through the character the tradition attaches to Mars, which centres on force, cutting and the handling of conflict. Whether that reading is right is not something a calculation can decide. What can be said is that it is the older attribution and the one that keeps the rulership scheme symmetrical.
Pluto, the modern answer
Pluto was identified in 1930 and was assigned to Scorpio soon after, in the same wave of reassignment that gave Uranus to Aquarius and Neptune to Pisces. The modern reading of Scorpio leans heavily on that assignment, emphasising transformation, concealment and what lies beneath a surface, which are associations that came with the new body rather than with Mars.
Neither attribution can be tested against anything, so a page that names one ruler without saying which scheme it belongs to has settled a live question quietly. The honest statement is that the sign has a traditional ruler and a modern one, and that a reading changes depending on which is used.
There is a practical consequence as well. Mars moves through the zodiac in about two years, so a chart ruler taken as Mars produces a placement that shifts noticeably between people born a few months apart. Pluto takes roughly two and a half centuries, so a chart ruler taken as Pluto sits in the same sign for everyone born across a span of years. The choice therefore changes how much the ruler can distinguish one chart from another.
Under the sign, and beyond it
Below the sign sits the face. The opening ten degrees of Scorpio go to Mars in the Chaldean order and to Scorpio itself in the triplicity scheme, which means the face attribution inherits the same ruler argument rather than resolving it.
Above and around all of it, the date fixes nothing else. The Moon covers the zodiac in under a month and can be in any sign on this birthday, changing sign during the day itself in many years. The ascendant runs through all twelve signs in twenty four hours and depends on where on earth the birth happened. The widget above takes your year, hour and birthplace, returns your exact solar degree, and reports how far it stood from the nearest sign boundary.
Questions people ask about this
What sign is 26 October?
Scorpio, in every year sampled at noon from 1930 to 2035. The Sun crossed the boundary around 23 October in all of them, so the date carries two degrees or more of margin.
Is Scorpio ruled by Mars or Pluto?
Traditionally Mars, which pairs Scorpio with Aries. Modern practice generally uses Pluto, assigned after its identification in 1930, and often keeps Mars alongside it. Both are conventions.
What degree of Scorpio is 26 October?
Between about two and three and a half degrees at noon across that century. The exact value for one birth depends on the year, the hour and the birthplace.
Which decan does this date fall in?
The first decan of Scorpio, zero to ten degrees. The Chaldean order gives it to Mars and the triplicity scheme gives it to Scorpio itself.
Could this date ever be Libra?
Not in the sampled century. Even in the years when the ingress falls latest, the Sun has been in Scorpio for two days or more by this date.
Does the ruler choice change my sun sign?
No. The sign is fixed by the Sun's longitude. The ruler is a layer of interpretation applied on top of it, and the choice affects the reading rather than the position.