Born May 21 – May 31
Gemini · first decan · Gemini at full signal, no filter
Your decan
The first decan of Gemini is the sign with nothing cutting the signal — double Mercury, pure restless mind. You're the most verbally alive, information-hungry, and mercurially scattered of the three Geminis, the one whose brain is always three tabs ahead of the conversation. There's no planet here to slow the feed or ask whether any of it matters.
What sets your third apart
Because Mercury rules both the sign and this decan, there's no second planet to lend weight, warmth, or staying power. It makes you the fastest thinker and sharpest talker of the three decans — and the most likely to skim everything and land nowhere. Brilliance without ballast isn't wisdom; it's a very entertaining loop.
Your gift
A mind that lights up any room — you connect dots nobody else even noticed were dots.
Your watch-out
Speed substitutes for depth; you're already onto the next idea before the first one did anything.
The exact degrees, and who rules them
A decan is a third of a sign: ten degrees of zodiac, not a mood. Yours is Gemini 0°00′ to 9°59′ — the first ten degrees the Sun crosses on its way through Gemini, roughly May 21 – May 31 in most years. Sun-sign dates shift by up to a day between years because the tropical year is not a whole number of days, so if you were born within about 24 hours of either end, run the actual chart rather than trusting a date table.
| Tradition | Ruler | What it governs |
|---|---|---|
| Sign ruler (all three decans) | Mercury | The baseline Gemini everyone shares |
| Chaldean face | Jupiter | growth, meaning and excess |
| Triplicity decanate | Mercury | mind, language and exchange |
The two systems disagree, which is normal and worth knowing: the Chaldean faces run the seven classical planets in speed order straight through all 36 decans without regard to sign boundaries, while the triplicity decanates give the first third of every sign to its own ruler and then step through the other signs of the same element. Most popular astrology quotes the triplicity ruler (Mercury) without saying so; the older Gemini face here is Jupiter.
Read either way, the point is the same: commentary — this third narrates itself, and thinks a feeling before it feels it.
How it actually shows up
The decan is a modifier, not a second sign. It shifts emphasis inside Gemini rather than replacing it — so everything true of Gemini is still true of you, with mind, language and exchange turned up. Three places people notice it:
- Under pressure. A Gemini sun typically reframes, jokes, changes the subject. In this third that reaction takes its colour from Mercury — mind, language and exchange is what the reaction ends up being about.
- In how you start things. The first decan sits at the front of the sign, where its qualities are least diluted and most raw.
- Next to the other two. Compare it directly: the second decan (Jun 1 – Jun 10) runs on Venus, and the third decan (Jun 11 – Jun 20) runs on Saturn. Same sign, three noticeably different settings.
What it is not: a personality test, and not something to weigh against your Moon or rising, both of which say considerably more about you than a third of your sun sign does. The big three is where to look next.
Your decan is a hint. Your chart is the answer.
The decan refines your sun sign — but your moon, rising and every planet are where the real story lives. Run your full birth chart, free.
Degree ranges are exact by definition (each decan is ten degrees of zodiac); the calendar dates shift by up to a day between years. Rulerships are the classical Chaldean face and triplicity decanate assignments, both stated above. Written and reviewed by the Zodiux editorial team · Last reviewed · How Zodiux computes your chart · Editorial standards · For reflection and entertainment, not advice.