In US birth records, the rarest Sun sign is Capricorn. We sorted a decade of daily birth counts from the CDC's National Center for Health Statistics (1994 to 2003), and fifteen years from the Social Security Administration (2000 to 2014), by the Sun's sign on each day, and Capricorn had the fewest births in both. The most common signs were Leo and Virgo, with Cancer close behind, because the US has more births in late summer and early autumn and fewer in winter.
Popular lists often name Aquarius as the rarest sign. In the data, Aquarius comes second or third. Here's the full ranking, why Capricorn ends up last, and what "rare" can and can't mean in astrology.
The twelve signs, from rarest to most common
In the CDC records for 1994 to 2003, the signs ranked like this, from fewest births to most:
- Capricorn
- Sagittarius
- Aquarius
- Pisces
- Scorpio
- Aries
- Taurus
- Libra
- Gemini
- Cancer
- Virgo
- Leo
The Social Security figures for 2000 to 2014 gave almost the same order. Capricorn was still last and Leo still first; the only changes were that Aquarius and Sagittarius swapped places, as did Aries and Scorpio. Over the CDC decade, Leo had roughly half a million more births than Capricorn.
If you count births per day instead of in total, Virgo edges ahead of Leo as the busiest sign. Leo comes out on top overall partly because it's one of the longer signs, as the next section explains.
These are US figures only. The daily counts were published by the data journalism site FiveThirtyEight from the two agencies' records, and the pattern in other countries can be quite different.
Why Capricorn comes last
Three things stack up against Capricorn.
It's the shortest sign. The Sun doesn't move at a constant speed through the zodiac. Earth is closest to the Sun in early January and moves fastest then, so the Sun appears to cross the winter signs more quickly. Capricorn lasts roughly 29 and a half days; Cancer, in early summer, lasts about 31 and a half. Two fewer days means fewer birthdays.
It falls in the quietest part of the year. In both datasets, January had the fewest births per day of any month, and September the most.
It contains the holidays. The single days with the fewest births in the CDC records were December 25, January 1 and December 24, followed by July 4. Births also dip around Thanksgiving, which usually falls in Sagittarius. The holiday dip is usually put down to fewer scheduled inductions and caesareans on those days. Christmas and New Year's both fall in Capricorn, and the sign takes the hit.
Put together, Capricorn is short, wintry and full of holidays. Nothing about the sign itself makes it rare. Our Capricorn traits page has the sign itself.
Why Leo and Virgo are the most common
The US birth calendar peaks from July to September. In the CDC decade, the busiest single dates were all in September, along with late August. That's the Leo and Virgo stretch, with Cancer just before it and Libra just after.
The reasons for the late-summer peak are debated. A popular explanation is that more babies are conceived during the winter holidays, nine months earlier. Weather, daylight and work and school calendars have all been suggested too, and the size of the peak varies between countries and decades.
Leo also gains from length. Because Earth moves slowest in early July, the summer signs last longer, and Leo and Cancer are both over 31 days. A long sign in the busiest season ends up at the top of the table.
The rarest birthday is a different question
The rarest single birthday is February 29, which only exists in leap years, so it turns up about once every four years. Leap-day babies are all Pisces.
After that, the rarest birthdays are the holidays: Christmas Day, New Year's Day, Christmas Eve and the Fourth of July in the US data. So if someone tells you they're a rare Capricorn born on Christmas Day, they have a fair point on both counts.
People born on the edge between two signs sometimes wonder whether they belong to the rarer one. The Sun is only ever in one sign at a time; our guide to zodiac cusp signs explains how to check, and a free birth chart gives your exact Sun degree.
Rarer than any Sun sign: placements that really are uncommon
Every Sun sign is shared by roughly one person in twelve. What makes a chart unusual is the combination.
Some combinations can't happen at all. Mercury never gets more than about 28 degrees from the Sun, so a Leo can't have Mercury in Libra or Gemini. Venus stays within about 47 degrees, so an Aries can't have Venus in Libra. Our guide to Mercury sign meaning explains why.
Other placements are genuinely less common:
- Venus retrograde at birth. Venus is retrograde only about six weeks out of every nineteen months.
- A large stellium, four or five planets packed into one sign.
- A grand cross, four planets locked in two oppositions and four squares.
Your Sun and Moon pairing, by contrast, is one of 144 combinations, all fairly evenly spread. If you'd like to see your own, the moon sign calculator finds your Moon.
What rarity can and can't tell you
Being a rare sign doesn't make anyone more special, and being a common one doesn't make you ordinary. The numbers describe when Americans tend to have babies, shaped by holidays, hospital schedules and the seasons. They say nothing about what Capricorns or Leos are like.
What astrology does say is that your Sun sign is one layer of many. The tropical zodiac used here is tied to the seasons, not the constellations, which is why the sidereal zodiac used in Vedic astrology would shuffle many people into a different sign and change this ranking too.
Questions readers ask
What is the most common zodiac sign?
In US birth data, Leo had the most births in total, with Virgo a close second and the busiest sign per day. Cancer came third. All three fall in the late-summer peak of the American birth calendar.
Is Aquarius the rarest zodiac sign?
Not in the US records we looked at. Aquarius ranked second or third rarest, behind Capricorn, with Sagittarius close by. It's often called the rarest online, but the counts don't support that.
What is the rarest birthday?
February 29, which only occurs in leap years. Among ordinary dates, Christmas Day and New Year's Day had the fewest births in the CDC records.
Does the rarest sign change from country to country?
It can. Birth seasons differ by country, climate, culture and hemisphere, so a ranking built from US data may not hold elsewhere. Capricorn's shortness is universal, though, because it comes from Earth's orbit.
