The third decan of Scorpio runs 20 to 30 degrees, roughly November 12 to November 21, ruled by Venus. What a decan is, where the idea came from, and the tarot card that shares these ten degrees.
The RubyAstro TeamPublished September 19, 2026Dates checked September 19, 20265 min read
Scorpio Third Decan: 20 to 30 degrees of Scorpio, ruled by Venus.
The short answerThe Scorpio third decan is 20 to 30 degrees of Scorpio, roughly November 12 to November 21. Its ruler is Venus, which adds charm, ease and an eye for what is pleasant to the sign. In the tarot the same ten degrees are the Seven of Cups.
The dates
The Sun covers about a degree a day, so a decan takes roughly ten days. These are the calendar dates the Sun spends in the third decan of Scorpio, computed across 1930 to 2035.
When the Sun is in the Scorpio third decan
Degrees
20 to 30 of Scorpio
Dates
November 12 to November 21
Length
10 days
Ruler
Venus
Sign ruler
Pluto and Mars
Tarot card
Seven of Cups
The first and last days shift a little between years, because the Earth's year is 365.2422 days rather than 365 and the whole zodiac drifts about six hours a year against the calendar. November 12 and November 21 are the edges, and both have their own page with the exact figures.
What a decan is, and where the idea came from
A decan is a third of a sign: ten degrees out of thirty, which the Sun crosses in about ten days. Twelve signs give thirty-six of them, and each one carries its own planetary ruler on top of the sign's. That makes a decan roughly three times more specific than a Sun sign while still needing nothing but a birth date.
The idea is older than the zodiac it now divides. The Egyptians used thirty-six groups of stars, each rising about forty minutes after the last, to tell the time at night. Ten of them were visible across a night, which is one of the threads that led to the day being divided into twenty-four hours rather than some rounder number. The decans were on coffin lids and temple ceilings a long time before anybody attached planets to them.
The planetary rulers came later, from Hellenistic astrology, and they run in what is called the Chaldean order: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon, which is the planets ranked by apparent speed from slowest to fastest. Starting at the first ten degrees of Aries and counting that sequence forward one decan at a time gives every decan its ruler, and it comes out the same every time because it is arithmetic rather than opinion.
Scorpio through Venus
Scorpio is Water and Fixed, ruled by Pluto and Mars, and the traits usually attached to it are intense, private, loyal, perceptive and all or nothing. Every Scorpio has that. What the third decan adds is Venus, and the result is a Scorpio who runs softer and more sociable.
In practice the pairing shows as making it attractive rather than forcing it. A Scorpio from this decan is recognisably Scorpio, with charm, ease and an eye for what is pleasant laid over the top. Compared with the other two thirds of the sign it is the Venus version, and the difference is usually obvious once you know to look for it.
The three decans of Scorpio side by side
Decan
Degrees
Ruler
What it adds
First
0 to 10
Mars
heat, urgency and a willingness to fight for it
Second
10 to 20
Sun
confidence, visibility and a wish to be seen doing it
Third (this one)
20 to 30
Venus
charm, ease and an eye for what is pleasant
That table is the argument for decans in one block. Three people can all be Scorpio and be running it through Mars, Sun and Venus, which is a genuine difference and one a Sun sign on its own throws away.
The tarot card for this decan
The standard English tarot deck was built on this same system. Every pip card from Two to Ten corresponds to one decan, which means the third decan of Scorpio and the Seven of Cups are two descriptions of one ten-degree stretch of sky.
That correspondence is not decoration and it is not something the tarot borrowed loosely. The Rider deck of 1909 was drawn to a scheme in which the thirty-six pips map onto the thirty-six decans in order, and the card's traditional meaning was derived from the decan's ruler and sign rather than the other way round. Reading the card is another way of reading these ten degrees, and it is frequently the more vivid one.
Venus in Scorpio is the third description of the same thing, this time as a birth chart placement.
If your birthday falls here
Your Sun is in this decan, which narrows it from one sign in twelve to one stretch in thirty-six. Worth doing something with: read the Venus pages as well as the Scorpio ones, because half of what is usually described as your sign is being coloured by a planet most descriptions never mention.
What a decan still cannot doIt narrows your Sun from a thirty-day band to a ten-day one, which is a real improvement and is still only your Sun. Your Moon can change sign inside a single day and your rising sign changes completely every two hours, so neither is anywhere in this. Anybody selling a decan reading as a full picture is selling you one tenth of a chart.
Roughly November 12 to November 21, which is 20 to 30 degrees of Scorpio. The edges move by a day either way between years.
Who rules the third decan of Scorpio?
Venus, from the Chaldean order counting forward from the first decan of Aries. Scorpio itself is ruled by Pluto and Mars.
What tarot card is the Scorpio third decan?
The Seven of Cups. Every pip card from Two to Ten corresponds to one decan, and this is the one.
How do I know which decan I am?
By your birth date, and more precisely by your Sun's degree. The first ten degrees of a sign are the first decan, ten to twenty the second, twenty to thirty the third.
RubyAstro writes about astrology for reflection and self-understanding. Nothing here is medical, legal or financial advice, and none of it is a prediction of events. Read our full disclaimer.