Were you born with Mercury retrograde?

About 1 in 5 people were born with Mercury retrograde. Between 1950 and 2050 Mercury was retrograde 19.2% of the time, in 319 separate spells of about three weeks. That makes it one of the more common things a birth chart can show.

We worked out every one of those spells, plus every Venus and Mars retrograde, from the same astronomy that draws Hali’s charts. Here is what the numbers show.

How common is it to be born with Mercury retrograde?

Mercury was retrograde for 19.2% of the 101 years from 1950 to 2050. If births are spread evenly through time, that is 192 in every 1,000 people, or about 1 in 5.2.

It happened 319 times, three or four times a year. Sixteen of the 101 years had four. Each spell lasted between 19.8 and 24.2 days, and 22.2 days on average.

Venus and Mars turn retrograde less often, so fewer people have them.

Planet	Share of time retrograde	About 1 person in	Per 1,000 people	Retrogrades, 1950 to 2050
Mercury	19.2%	5.2	192	319
Venus	7.3%	13.7	73	64
Mars	9.6%	10.4	96	48

How many people in a room were born with Mercury retrograde?

In a group of 10 people, you would expect about 1.9 to have Mercury retrograde. The most likely number is 2, with a 30.1% chance, and there is an 11.9% chance that nobody in the group has it.

In a class of 30, expect about 5.8. The most likely number is 5, and the chance that none of the 30 has it is just 0.2%.

Those figures assume birthdays picked at random from the whole century. A real class is mostly born within one school year, and the share moves a little from year to year, from 18.2% in 1956, 2008 and 2028 to 22.9% in 2036.

Are some birthdays more often Mercury retrograde than others?

A little, but much less than you might expect. Across the 365 dates of the year, the share runs from 16.8% on 20 June and 27 November to 22.2% on 31 August. The typical date sits within about 1 point of the average of 19.2%.

Put another way, at midday UTC on 31 August Mercury was retrograde in 23 of the 101 years. On 20 June it was retrograde in 17. Every date in the calendar has it in some years and not in others, so no birthday is safe from it and none is guaranteed it.

Average 19.2%

0%10%20%

19.4%

JanJ

18.9%

FebF

19.3%

MarM

19.7%

AprA

19.1%

MayM

18.2%

JunJ

19%

JulJ

20.5%

AugA

20.4%

SepS

18.7%

OctO

18.1%

NovN

19%

DecD

Each bar is the average for every date in that month, 1950 to 2050. The line marks the overall average. The scale starts at zero, so you can see how even it is.

Month by month figures

Month	Share of births
January	19.4%
February	18.9%
March	19.3%
April	19.7%
May	19.1%
June	18.2%
July	19%
August	20.5%
September	20.4%
October	18.7%
November	18.1%
December	19%

By month, August is highest at 20.5% and November lowest at 18.1%.

Why is it so even? Two effects almost cancel out. Mercury’s orbit is lopsided, so its retrogrades don’t fall evenly through the year and they don’t all last the same time. The ones centred in June and July last longest, 24.0 and 24.2 days on average, but they are among the rarest, with 23 and 24 of them in 101 years. The ones centred in December and January are the shortest, 19.8 and 20.4 days, but the most frequent, with 29 and 31. Long but rare and short but frequent end up covering almost the same share of the calendar.

Is the late summer bump real? Partly. We ran the same sums for the 100 years either side of our window. From 1850 to 1949 the highest month was September at 20.0%, and from 2051 to 2150 it was August at 20.4%. The lowest month was December both times, at 18.1% and 18.2%. So late summer birthdays do come out slightly ahead in every century we checked, but the exact top date changes, and the gap is never more than about two points.

What about 29 February? It only came round 25 times in our window, and Mercury was retrograde at midday UTC in 4 of them. That is too few years to compare fairly, so leap day is left out of the rankings.

Venus and Mars are much more uneven

Venus is the opposite of Mercury. Its retrogrades come back to almost the same dates every eight years, five retrogrades to every eight-year cycle, so some birthdays get them again and again and others almost never do. Across the calendar the share for Venus runs from 0% to 12.9%. On 11 dates, including 6 to 11 December, Venus was not retrograde once in 101 years.

Mars turns retrograde about every two years and two months, and its retrogrades only come back to similar dates after about 15 or 17 years. Its share by date runs from 5.0% to 14.9%.

How rare is it to be born with two or more planets retrograde?

Counting just Mercury, Venus and Mars, 32.5% of the time at least one of them was retrograde, about 1 person in 3. The other 67.5% of the time all three were moving forward.

Two or more at once is much rarer, at 3.5% of the time, about 1 person in 28. Mercury and Mars together account for 2.2%, Mercury and Venus for 1.3%, and Venus and Mars for only 0.05%.

All three at once happens only once in the whole 101 years, for 4.1 days from 14 to 18 December 2037. Babies born in those few days will be the only people in the period with all three retrograde.

What does Mercury retrograde in a birth chart mean?

First, the astronomy, which is real. Mercury never actually moves backwards. Every few months it passes between the Earth and the Sun, and as it overtakes us on the inside lane it appears to drift backwards against the stars for about three weeks. Astrologers call that apparent motion retrograde.

What it means in a birth chart is a matter of interpretation, and astrologers don’t agree. There is no scientific evidence that a retrograde planet shapes personality, so read what follows as what astrologers say, not as fact.

The traditional view. Older astrology treated a retrograde planet as weakened, a little like a messenger walking the wrong way. William Lilly’s Christian Astrology (1647), one of the best known English textbooks, scores retrograde as a debility worth minus 5 in his table of a planet’s strengths and weaknesses.

The modern view. Many modern astrologers read natal Mercury retrograde more kindly, as a mind that works inward first. People with it are often described as thinking things through privately before speaking, revisiting ideas, writing better than they talk, or coming at a problem from an unusual angle. Writers such as Erin Sullivan, in Retrograde Planets (1992), treat retrograde planets as pointing towards reflection rather than weakness. Other astrologers give a natal retrograde little weight on its own and only read it alongside Mercury’s sign, house and aspects.

Whichever view you like, remember that about 1 person in 5 has it. It can describe a tendency, never a verdict, and the rest of your chart matters far more. Being born with Mercury retrograde is also a different thing from the Mercury retrograde spells people blame for lost emails. One is a fixed feature of your chart, the other comes round three or four times a year for everyone.

What if I was born when Mercury turned?

Twice in every retrograde, Mercury slows, stops and turns. Astrologers call a planet in that state stationary, and many treat a stationary planet in a birth chart as especially strong.

Right at the turn, a planet moves so little in an hour that the answer depends on the exact minute. Hali works out every planet from the Earth’s centre, so our birth charts and this tool agree at every turn of Mercury, Venus and Mars from 1950 to 2050. If you were born on a day a planet turned and you leave out the time, the tool says so and shows the minute it turned.

Mercury retrograde dates, 1950 to 2050

Every Mercury retrograde in our window, year by year, with the share of each year it took up. Dates are in UTC. If you were born close to a turn, the date where you were born may be a day different, and the tool above works that out for your time and place.

Show every year from 1950 to 2050

Year	Mercury retrograde	Share of year
1950	8 Jan to 29 Jan, Aquarius into Capricorn3 May to 27 May, in Taurus3 Sept to 26 Sept, Libra into Virgo23 Dec to 12 Jan 1951, in Capricorn	20.6%
1951	14 Apr to 8 May, Taurus into Aries17 Aug to 9 Sept, in Virgo7 Dec to 27 Dec, Capricorn into Sagittarius	21.5%
1952	26 Mar to 19 Apr, in Aries29 Jul to 22 Aug, in Leo20 Nov to 10 Dec, in Sagittarius	18.3%
1953	9 Mar to 1 Apr, Aries into Pisces11 Jul to 4 Aug, Leo into Cancer3 Nov to 23 Nov, Sagittarius into Scorpio	18.4%
1954	20 Feb to 14 Mar, in Pisces23 Jun to 17 Jul, in Cancer18 Oct to 7 Nov, Scorpio into Libra	18.4%
1955	3 Feb to 25 Feb, in Aquarius3 Jun to 27 Jun, in Gemini1 Oct to 22 Oct, in Libra	18.3%
1956	18 Jan to 8 Feb, Aquarius into Capricorn14 May to 7 Jun, in Gemini13 Sept to 5 Oct, Libra into Virgo	18.2%
1957	1 Jan to 21 Jan, in Capricorn25 Apr to 19 May, in Taurus27 Aug to 19 Sept, in Virgo16 Dec to 5 Jan 1958, Capricorn into Sagittarius	22.6%
1958	6 Apr to 30 Apr, Taurus into Aries9 Aug to 2 Sept, Virgo into Leo30 Nov to 20 Dec, in Sagittarius	19.5%
1959	19 Mar to 12 Apr, in Aries22 Jul to 15 Aug, in Leo14 Nov to 3 Dec, Sagittarius into Scorpio	18.4%
1960	1 Mar to 24 Mar, in Pisces3 Jul to 27 Jul, Leo into Cancer27 Oct to 16 Nov, in Scorpio	18.3%
1961	12 Feb to 6 Mar, Pisces into Aquarius14 Jun to 8 Jul, in Cancer10 Oct to 31 Oct, Scorpio into Libra	18.3%
1962	27 Jan to 17 Feb, in Aquarius26 May to 19 Jun, in Gemini24 Sept to 15 Oct, in Libra	18.3%
1963	11 Jan to 1 Feb, Aquarius into Capricorn6 May to 30 May, Gemini into Taurus6 Sept to 29 Sept, Libra into Virgo26 Dec to 15 Jan 1964, in Capricorn	19.8%
1964	16 Apr to 10 May, in Taurus19 Aug to 11 Sept, in Virgo9 Dec to 29 Dec, Capricorn into Sagittarius	22.2%
1965	29 Mar to 22 Apr, in Aries1 Aug to 25 Aug, Virgo into Leo23 Nov to 12 Dec, in Sagittarius	18.4%
1966	12 Mar to 4 Apr, Aries into Pisces14 Jul to 7 Aug, in Leo6 Nov to 26 Nov, Sagittarius into Scorpio	18.4%
1967	23 Feb to 17 Mar, in Pisces26 Jun to 20 Jul, in Cancer21 Oct to 10 Nov, in Scorpio	18.4%
1968	6 Feb to 28 Feb, Pisces into Aquarius6 Jun to 30 Jun, Cancer into Gemini3 Oct to 24 Oct, Scorpio into Libra	18.3%
1969	20 Jan to 10 Feb, in Aquarius17 May to 10 Jun, in Gemini16 Sept to 8 Oct, Libra into Virgo	18.3%
1970	4 Jan to 24 Jan, Aquarius into Capricorn28 Apr to 22 May, in Taurus30 Aug to 21 Sept, in Virgo19 Dec to 8 Jan 1971, Capricorn into Sagittarius	21.8%
1971	9 Apr to 3 May, Taurus into Aries12 Aug to 5 Sept, Virgo into Leo3 Dec to 22 Dec, in Sagittarius	20.3%
1972	21 Mar to 14 Apr, in Aries24 Jul to 17 Aug, in Leo15 Nov to 5 Dec, Sagittarius into Scorpio	18.4%
1973	4 Mar to 27 Mar, in Pisces6 Jul to 30 Jul, Leo into Cancer30 Oct to 19 Nov, in Scorpio	18.4%
1974	15 Feb to 9 Mar, Pisces into Aquarius17 Jun to 12 Jul, in Cancer13 Oct to 3 Nov, Scorpio into Libra	18.3%
1975	30 Jan to 20 Feb, in Aquarius29 May to 22 Jun, in Gemini26 Sept to 18 Oct, in Libra	18.3%
1976	14 Jan to 3 Feb, Aquarius into Capricorn9 May to 2 Jun, Gemini into Taurus8 Sept to 1 Oct, Libra into Virgo28 Dec to 17 Jan 1977, in Capricorn	19.3%
1977	20 Apr to 13 May, in Taurus22 Aug to 14 Sept, in Virgo12 Dec to 31 Dec, Capricorn into Sagittarius	22.7%
1978	1 Apr to 25 Apr, in Aries4 Aug to 28 Aug, Virgo into Leo25 Nov to 15 Dec, in Sagittarius	18.4%
1979	15 Mar to 7 Apr, Aries into Pisces17 Jul to 11 Aug, in Leo9 Nov to 29 Nov, Sagittarius into Scorpio	18.4%
1980	26 Feb to 19 Mar, in Pisces28 Jun to 22 Jul, in Cancer23 Oct to 12 Nov, in Scorpio	18.3%
1981	8 Feb to 2 Mar, Pisces into Aquarius9 Jun to 3 Jul, Cancer into Gemini6 Oct to 27 Oct, Scorpio into Libra	18.3%
1982	23 Jan to 13 Feb, in Aquarius21 May to 13 Jun, in Gemini19 Sept to 11 Oct, in Libra	18.3%
1983	7 Jan to 27 Jan, Aquarius into Capricorn1 May to 25 May, in Taurus2 Sept to 24 Sept, Libra into Virgo22 Dec to 11 Jan 1984, in Capricorn	21.1%
1984	11 Apr to 5 May, Taurus into Aries14 Aug to 7 Sept, in Virgo4 Dec to 24 Dec, Capricorn into Sagittarius	21%
1985	24 Mar to 17 Apr, in Aries28 Jul to 20 Aug, in Leo18 Nov to 8 Dec, Sagittarius into Scorpio	18.4%
1986	7 Mar to 30 Mar, Aries into Pisces9 Jul to 3 Aug, Leo into Cancer2 Nov to 22 Nov, in Scorpio	18.4%
1987	18 Feb to 12 Mar, Pisces into Aquarius21 Jun to 15 Jul, in Cancer16 Oct to 6 Nov, Scorpio into Libra	18.4%
1988	2 Feb to 23 Feb, in Aquarius31 May to 24 Jun, in Gemini28 Sept to 20 Oct, in Libra	18.3%
1989	16 Jan to 5 Feb, Aquarius into Capricorn12 May to 5 Jun, Gemini into Taurus11 Sept to 3 Oct, Libra into Virgo30 Dec to 20 Jan 1990, in Capricorn	18.6%
1990	23 Apr to 17 May, in Taurus25 Aug to 17 Sept, in Virgo14 Dec to 3 Jan 1991, Capricorn into Sagittarius	22.7%
1991	4 Apr to 28 Apr, in Aries7 Aug to 31 Aug, Virgo into Leo28 Nov to 18 Dec, in Sagittarius	19.1%
1992	17 Mar to 9 Apr, Aries into Pisces20 Jul to 13 Aug, in Leo11 Nov to 1 Dec, Sagittarius into Scorpio	18.4%
1993	27 Feb to 22 Mar, in Pisces1 Jul to 25 Jul, in Cancer25 Oct to 15 Nov, in Scorpio	18.4%
1994	11 Feb to 5 Mar, Pisces into Aquarius12 Jun to 6 Jul, Cancer into Gemini9 Oct to 30 Oct, Scorpio into Libra	18.3%
1995	26 Jan to 16 Feb, in Aquarius24 May to 17 Jun, in Gemini22 Sept to 14 Oct, in Libra	18.3%
1996	9 Jan to 30 Jan, Aquarius into Capricorn3 May to 27 May, in Taurus4 Sept to 26 Sept, Libra into Virgo23 Dec to 12 Jan 1997, in Capricorn	20.5%
1997	14 Apr to 8 May, Taurus into Aries17 Aug to 10 Sept, in Virgo7 Dec to 27 Dec, Capricorn into Sagittarius	21.5%
1998	27 Mar to 20 Apr, in Aries31 Jul to 23 Aug, in Leo21 Nov to 11 Dec, in Sagittarius	18.4%
1999	10 Mar to 2 Apr, Aries into Pisces12 Jul to 6 Aug, Leo into Cancer5 Nov to 25 Nov, Sagittarius into Scorpio	18.4%
2000	21 Feb to 14 Mar, in Pisces23 Jun to 17 Jul, in Cancer18 Oct to 8 Nov, Scorpio into Libra	18.3%
2001	4 Feb to 25 Feb, Pisces into Aquarius4 Jun to 28 Jun, in Gemini1 Oct to 22 Oct, in Libra	18.3%
2002	18 Jan to 8 Feb, Aquarius into Capricorn15 May to 8 Jun, in Gemini14 Sept to 6 Oct, Libra into Virgo	18.3%
2003	2 Jan to 23 Jan, in Capricorn26 Apr to 20 May, in Taurus28 Aug to 20 Sept, in Virgo17 Dec to 6 Jan 2004, Capricorn into Sagittarius	22.3%
2004	6 Apr to 30 Apr, Taurus into Aries10 Aug to 2 Sept, Virgo into Leo30 Nov to 20 Dec, in Sagittarius	19.8%
2005	19 Mar to 12 Apr, in Aries23 Jul to 16 Aug, in Leo14 Nov to 4 Dec, Sagittarius into Scorpio	18.4%
2006	2 Mar to 25 Mar, in Pisces4 Jul to 29 Jul, Leo into Cancer28 Oct to 17 Nov, in Scorpio	18.4%
2007	14 Feb to 8 Mar, Pisces into Aquarius15 Jun to 10 Jul, in Cancer12 Oct to 1 Nov, Scorpio into Libra	18.3%
2008	28 Jan to 19 Feb, in Aquarius26 May to 19 Jun, in Gemini24 Sept to 15 Oct, in Libra	18.2%
2009	11 Jan to 1 Feb, Aquarius into Capricorn7 May to 31 May, Gemini into Taurus7 Sept to 29 Sept, Libra into Virgo26 Dec to 15 Jan 2010, in Capricorn	19.8%
2010	18 Apr to 11 May, in Taurus20 Aug to 12 Sept, in Virgo10 Dec to 30 Dec, Capricorn into Sagittarius	22.3%
2011	30 Mar to 23 Apr, in Aries3 Aug to 26 Aug, Virgo into Leo24 Nov to 14 Dec, in Sagittarius	18.4%
2012	12 Mar to 4 Apr, Aries into Pisces15 Jul to 8 Aug, in Leo6 Nov to 26 Nov, Sagittarius into Scorpio	18.4%
2013	23 Feb to 17 Mar, in Pisces26 Jun to 20 Jul, in Cancer21 Oct to 10 Nov, in Scorpio	18.4%
2014	6 Feb to 28 Feb, Pisces into Aquarius7 Jun to 1 Jul, Cancer into Gemini4 Oct to 25 Oct, Scorpio into Libra	18.3%
2015	21 Jan to 11 Feb, in Aquarius19 May to 11 Jun, in Gemini17 Sept to 9 Oct, in Libra	18.3%
2016	5 Jan to 25 Jan, Aquarius into Capricorn28 Apr to 22 May, in Taurus30 Aug to 22 Sept, in Virgo19 Dec to 8 Jan 2017, Capricorn into Sagittarius	21.7%
2017	9 Apr to 3 May, Taurus into Aries13 Aug to 5 Sept, Virgo into Leo3 Dec to 23 Dec, in Sagittarius	20.4%
2018	22 Mar to 15 Apr, in Aries26 Jul to 19 Aug, in Leo17 Nov to 6 Dec, Sagittarius into Scorpio	18.4%
2019	5 Mar to 28 Mar, in Pisces7 Jul to 1 Aug, Leo into Cancer31 Oct to 20 Nov, in Scorpio	18.4%
2020	17 Feb to 10 Mar, Pisces into Aquarius18 Jun to 12 Jul, in Cancer14 Oct to 3 Nov, Scorpio into Libra	18.3%
2021	30 Jan to 21 Feb, in Aquarius29 May to 22 Jun, in Gemini27 Sept to 18 Oct, in Libra	18.3%
2022	14 Jan to 4 Feb, Aquarius into Capricorn10 May to 3 Jun, Gemini into Taurus10 Sept to 2 Oct, Libra into Virgo29 Dec to 18 Jan 2023, in Capricorn	19%
2023	21 Apr to 15 May, in Taurus23 Aug to 15 Sept, in Virgo13 Dec to 2 Jan 2024, Capricorn into Sagittarius	22.8%
2024	1 Apr to 25 Apr, in Aries5 Aug to 28 Aug, Virgo into Leo26 Nov to 15 Dec, in Sagittarius	18.6%
2025	15 Mar to 7 Apr, Aries into Pisces18 Jul to 11 Aug, in Leo9 Nov to 29 Nov, Sagittarius into Scorpio	18.4%
2026	26 Feb to 20 Mar, in Pisces29 Jun to 23 Jul, in Cancer24 Oct to 13 Nov, in Scorpio	18.4%
2027	9 Feb to 3 Mar, Pisces into Aquarius10 Jun to 4 Jul, Cancer into Gemini7 Oct to 28 Oct, Scorpio into Libra	18.3%
2028	24 Jan to 14 Feb, in Aquarius21 May to 14 Jun, in Gemini19 Sept to 11 Oct, in Libra	18.2%
2029	7 Jan to 27 Jan, Aquarius into Capricorn1 May to 25 May, in Taurus2 Sept to 25 Sept, Libra into Virgo22 Dec to 11 Jan 2030, in Capricorn	21%
2030	13 Apr to 6 May, Taurus into Aries16 Aug to 8 Sept, in Virgo6 Dec to 25 Dec, Capricorn into Sagittarius	21.1%
2031	26 Mar to 18 Apr, in Aries29 Jul to 22 Aug, in Leo19 Nov to 9 Dec, Sagittarius into Scorpio	18.4%
2032	7 Mar to 30 Mar, Aries into Pisces10 Jul to 3 Aug, Leo into Cancer2 Nov to 22 Nov, Sagittarius into Scorpio	18.4%
2033	18 Feb to 13 Mar, in Pisces21 Jun to 15 Jul, in Cancer16 Oct to 6 Nov, Scorpio into Libra	18.4%
2034	2 Feb to 23 Feb, in Aquarius2 Jun to 26 Jun, in Gemini30 Sept to 21 Oct, in Libra	18.3%
2035	17 Jan to 7 Feb, Aquarius into Capricorn13 May to 6 Jun, Gemini into Taurus13 Sept to 5 Oct, Libra into Virgo	18.3%
2036	1 Jan to 21 Jan, in Capricorn23 Apr to 17 May, in Taurus25 Aug to 17 Sept, in Virgo15 Dec to 3 Jan 2037, Capricorn into Sagittarius	22.9%
2037	4 Apr to 28 Apr, Taurus into Aries8 Aug to 31 Aug, Virgo into Leo28 Nov to 18 Dec, in Sagittarius	19.2%
2038	18 Mar to 10 Apr, Aries into Pisces21 Jul to 14 Aug, in Leo12 Nov to 2 Dec, Sagittarius into Scorpio	18.4%
2039	1 Mar to 23 Mar, in Pisces2 Jul to 27 Jul, in Cancer27 Oct to 16 Nov, in Scorpio	18.4%
2040	12 Feb to 5 Mar, Pisces into Aquarius12 Jun to 7 Jul, in Cancer9 Oct to 30 Oct, Scorpio into Libra	18.3%
2041	26 Jan to 16 Feb, in Aquarius24 May to 17 Jun, in Gemini22 Sept to 14 Oct, in Libra	18.3%
2042	10 Jan to 30 Jan, Aquarius into Capricorn5 May to 29 May, in Taurus5 Sept to 27 Sept, Libra into Virgo25 Dec to 14 Jan 2043, in Capricorn	20.2%
2043	16 Apr to 9 May, in Taurus19 Aug to 11 Sept, in Virgo8 Dec to 28 Dec, Capricorn into Sagittarius	21.9%
2044	28 Mar to 20 Apr, in Aries31 Jul to 24 Aug, in Leo21 Nov to 11 Dec, in Sagittarius	18.3%
2045	10 Mar to 2 Apr, Aries into Pisces13 Jul to 6 Aug, Leo into Cancer5 Nov to 25 Nov, Sagittarius into Scorpio	18.4%
2046	21 Feb to 16 Mar, in Pisces24 Jun to 18 Jul, in Cancer19 Oct to 9 Nov, in Scorpio	18.4%
2047	5 Feb to 26 Feb, Pisces into Aquarius5 Jun to 29 Jun, Cancer into Gemini3 Oct to 24 Oct, Scorpio into Libra	18.3%
2048	20 Jan to 9 Feb, Aquarius into Capricorn16 May to 8 Jun, in Gemini15 Sept to 7 Oct, Libra into Virgo	18.2%
2049	2 Jan to 23 Jan, in Capricorn26 Apr to 20 May, in Taurus28 Aug to 20 Sept, in Virgo17 Dec to 6 Jan 2050, Capricorn into Sagittarius	22.2%
2050	8 Apr to 1 May, Taurus into Aries11 Aug to 3 Sept, Virgo into Leo1 Dec to 21 Dec, in Sagittarius	19.9%

How we calculated this

We used astronomy-engine, the MIT licensed library based on NASA JPL ephemerides that calculates every Hali chart. A planet counts as retrograde when its apparent longitude along the zodiac is lower one hour later, the same rule our birth charts use, measured from the Earth’s centre. We stepped through every day from mid 1949 to mid 2051, found each change of direction to within a second, and rounded every turn to the nearest minute.

The window is 1 January 1950 to 31 December 2050, 101 whole years, in UTC. For each calendar date we averaged, over every year that has that date, how much of the day the planet spent retrograde. The share of people assumes births are spread evenly in time. Real births are a little uneven by season and weekday, which would nudge the figures for individual dates but hardly moves the overall share, because Mercury retrogrades turn up in every season.

The group figures assume each person’s birth moment is picked at random from the whole window, and use the standard binomial formula. As a cross-check, our station times agree with the separately computed dates behind our Mercury retrograde and Venus retrograde pages to within 31 minutes for Mercury, 35 minutes for Venus and 34 minutes for Mars. The script that builds the dataset is in our code, so every number on this page can be rebuilt.

Use this data

The full dataset, every calendar date with the share of births with Mercury, Venus and Mars retrograde, is free to use under a Creative Commons Attribution licence (CC BY 4.0). Download the CSV. If you write about it, please credit Hali and link to this page. For questions or custom cuts of the data, contact us at hello@haliknows.com.

Want to see where Mercury sits in your own chart? The free birth chart shows every planet, with a mark on any that were retrograde when you were born.

<a href="https://haliknows.com/born-mercury-retrograde"><img src="https://haliknows.com/charts/born-mercury-retrograde.png" alt="Bar chart of how often each planet was retrograde from 1950 to 2050. Mercury was retrograde 19.2% of the time, about 1 in 5.2 people, Venus 7.3% and Mars 9.6%." width="1200" height="630" style="max-width:100%;height:auto"></a>
<p>Chart by <a href="https://haliknows.com/born-mercury-retrograde">Hali</a>, CC BY 4.0</p>