♊︎ Sun at ~10° Gemini · second decan · Mars

May 31 zodiac sign: Gemini, second decan

If you were born on May 31, your sign is Gemini, the air sign ruled by Mercury: the Sun is in Gemini on this date in every year from 1980 to 2030. The Sun sits about 10° into Gemini on this date, in the second decan, where Gemini's core takes on a Mars flavour. Here's what the date fixes, and what only your birth time can tell you.

Your sign: Gemini

The mutable air sign that lives by language — quick to learn, quick to pivot, quick to bore.

A Gemini Sun makes a mind that genuinely runs faster than most. You learn quickly, talk quickly, and link ideas across domains in a way that surprises specialists. Your gift is the connection — between two unrelated fields, between two people who'd never meet without you, between an old idea and a new use for it. You're a natural translator.

The date fixes the Sun; the hour fixes the rest. A Gemini born May 31 in the late evening has Aquarius rising, and a different first impression from one born at dawn. Your rising sign needs the birth time; the twelve Gemini Sun combinations show what each one changes.

Gemini dates, traits & compatibility → · What a Gemini birth chart looks like →

In the US (2000–2014), an average of 11,035 babies were born on each May 31, rank 279 of 366 dates; Gemini is number 4 of 12 signs (8.56%). What's the most common zodiac sign?

The Moon on May 31, 1980–2030

Across the 51 years from 1980 to 2030, the Moon at noon UTC on May 31 was most often in Aries, Gemini, Virgo, Sagittarius, and Pisces (5 years each) and least often in Cancer and Aquarius (3 years each). Unlike the Sun, the Moon sign depends on the birth year. On May 31, 2026, the Moon stays in Sagittarius the whole UTC day.

In 23 of those 51 years (45%) the Moon changed sign during May 31 itself, so in those years the birth time decides the Moon as well as the rising sign. Cells with an arrow mark them, with the UTC time of the change. The Moon was exactly full on May 31 in 1988 and 2026, and new in 2003.

Find your birth year. One sign means the Moon spent the whole UTC day there; an arrow means it changed sign that day, at the UTC time shown: born before it, the first sign; after it, the second. The Moon sign calculator settles it in seconds; your birth chart adds the rising sign and houses.

Times in UTC: a birth late in the evening in the Americas, or early in the morning in Asia, can fall on the neighbouring UTC date.

May 2026: full moon May 1, 2026, Scorpio / May 31, 2026, Sagittarius · new moon May 16, 2026, Taurus.

Your decan: the second decan of Gemini

Each sign is divided into three 10° decans, and each decan has a sub-ruler that shades the sign's core. Degrees 10–20 of Gemini belong to Mars: your drive — how you take action, what makes you angry, and what you fight for. Read it as Gemini with a Mars accent — the air core is unchanged, the emphasis moves.

May 31 sits on a decan boundary: in 48 of the 51 years from 1980 to 2030 the Sun spends part or all of the day (UTC) in the first decan of Gemini (0°–10°), sub-ruled by Jupiter. Which one is yours depends on your birth year and time; a birth chart gives the exact degree.

Decan tarot card · Golden Dawn attribution

Nine of Swords

Worry · Sleepless nights · Dread. The card assigned to this ten-degree slice of the zodiac — a birthday card in the same sense a sun sign is a birthday sign: one lens on the date, not a verdict.

Read the Nine of Swords in full on My Day Check →

All the tarot cards for May 31: decan, sign, ruling planet and year card →

What the date can't tell you

The Sun is one placement out of ten. Your Moon sign changes every two to three days, so Geminis born on May 31 in different years have different Moons; your rising sign changes every two hours and needs a birth time and place. Those two carry most of what people mean by "personality" in a chart.

Born May 31? Add your year, time and place

Your Moon and rising depend on the year and hour. Computed here in a few seconds — then your full chart with a preview of its reading, no sign-up.

Or browse the twelve possibilities: Gemini Sun with each Moon → · just my Moon sign · how the free birth chart calculator works

Classic matches for a May 31 birthday

By sun sign, Gemini pairs most easily with Libra, Aquarius, Aries, Leo. Sun-sign compatibility is the coarse layer; the couple reading compares both full charts.

Common questions

What zodiac sign is May 31?

May 31 is Gemini, the mutable air sign ruled by Mercury. The Sun sits at roughly 10° Gemini on this date, in the second decan.

What decan is May 31?

The second decan of Gemini (10°–20°), sub-ruled by Mars. Decans divide each sign into three 10° slices; the sub-ruler adds a second flavour to the sign's core — here your drive — how you take action, what makes you angry, and what you fight for. May 31 sits on a decan boundary: in 48 of the 51 years from 1980 to 2030 the Sun spends part or all of the day (UTC) in the first decan of Gemini (0°–10°), sub-ruled by Jupiter. Which one is yours depends on your birth year and time; a birth chart gives the exact degree.

What tarot card is May 31?

In the Golden Dawn system each decan has a minor arcana card: for the second decan of Gemini it is the Nine of Swords (worry, sleepless nights, dread). It's a birthday card in the same way a sun sign is — one lens, not a verdict.

What Moon sign is someone born on May 31?

It depends on the year, and in 45% of years on the hour too. For example: in 1980, Sagittarius or Capricorn; in 1990, Virgo; in 2000, Taurus; in 2010, Capricorn; in 2020, Virgo or Libra. Over 1980–2030 the Moon on May 31 was most often in Aries, Gemini, Virgo, Sagittarius, and Pisces. A birth time and place pin it down.

Does everyone born on May 31 have the same chart?

No. They share the Sun in Gemini, but the Moon changes sign every two to three days, the rising sign every two hours, and the outer planets by year. Two people born May 31 in different years can have almost nothing else in common in their charts.