How often each planet is retrograde, 1900–2100

Key findings

• Mercury turns retrograde three or four times a year, for 19.8–24.2 days each time: 19.1% of the time, about 70 days a year. It turns retrograde three times in 171 of the 201 years and four times in 30, the next being 2029.
• Venus is the least often retrograde planet, at 7.2%. From Venus outwards the share grows with distance from the Sun, up to 44.1% for Pluto, which is retrograde about 161 days a year.
• At least one planet is retrograde 93.2% of the time, and on average 2.3 are retrograde at once. Time with no planet retrograde at all adds up to 6.8%; the longest such stretch in the 201 years ran from 22 January to 21 April 2023 (88 days).
• Seven of the eight are retrograde at once on only four occasions: 6–10 Jan 1944, 29 Apr–5 May 1984, 12–15 Jul 1986 and 16–18 Sep 2082. Venus is the one moving forward in 1944, 1984 and 1986, Neptune in 2082. At no moment in these 201 years are all eight retrograde together.
• An independent search with NASA JPL’s DE440 ephemeris finds the same 3,660 stations, and the station times agree to within 1.3 minutes for every planet.

Mercury retrograde dates, 2026–2030

Dates are UT. Where you live the station can fall on the calendar day before or after; the time to the minute is in the CSV.

Years with four Mercury retrogrades from now on: 2029, 2036, 2042, 2049, 2055, 2062, 2068, 2075, 2082, 2088 and 2095. Mercury passes between the Earth and the Sun about every 116 days, so three of its cycles take about 348 days, some 17 days less than a year. A fourth fits into a calendar year only when the first station of the year falls in roughly the first two and a half weeks of January, which happens every six or seven years.

Over the 201 years the station retrograde falls most often in Scorpio and Sagittarius (58 times each) and least often in Gemini and Cancer (46 times each), against an average of 53 per sign. This is orbital geometry: Mercury’s orbit is markedly elongated, it moves fastest near its perihelion, and it passes between the Earth and the Sun more often on that side of its orbit, which we see against Scorpio and Sagittarius.

Other planets: retrograde periods in 2026–2027

Including the periods already under way on 1 January 2026.

Every period of every planet from 1900 to 2100 is in the CSV below.

Retrograde statistics by planet, 1900–2100

Share of the 201 years spent retrograde, number of complete retrograde periods, how long they last and how far back the planet moves. Periods already under way on 1 January 1900 or still running at the end of 2100 count towards the share but not towards the other columns.

The farther out a planet, the slower it moves, so the Earth laps it roughly once a year and it spends a larger part of each lap going backwards: 30% for Jupiter, 36% for Saturn, 41–44% for Uranus to Pluto. Mars takes almost two years to go round the Sun, so the Earth gains on it slowly and catches it only about every 26 months, and it is retrograde 9.4% of the time. Mercury and Venus appear to reverse around the time they pass between the Earth and the Sun.

How many planets are retrograde at once

Share of the 201 years with exactly this many of the eight retrograde, computed from the station times without sampling.

Time with nothing retrograde comes in 160 separate stretches over the 201 years; 23 of them last longer than 60 days.

Method

• A planet is retrograde while its apparent geocentric ecliptic longitude decreases. Positions come from Swiss Ephemeris 2.10.03 with its built-in Moshier ephemeris (no data files needed). They are apparent and tropical, referred to the true equinox of date, as in a birth chart; for Jupiter to Pluto they are the centre of mass of the planet and its moons, the Swiss Ephemeris default.
• The speed is the change of the longitude over ±30 minutes. It is sampled once a day from 1 January 1900 to the end of 2100, and every point where it changes from positive to negative or back is refined by bisection to within one second; station times are then rounded to the minute. A change from direct to retrograde motion is a station retrograde, the reverse a station direct, and a retrograde period runs from one to the next. Times are UT.
• “How many at once” is computed from the station times, without sampling: the stations of all eight are merged into one timeline and the time between consecutive stations is added to the current count. The Sun and the Moon are never retrograde; the lunar nodes, Chiron and asteroids are not counted. Pluto, classed as a dwarf planet since 2006, is included because birth charts use it; “the eight” here means Mercury to Pluto.
• Independent check: the same search repeated with a different program and a different ephemeris, Skyfield with NASA JPL’s DE440 (file de440s.bsp), the speed again taken over ±30 minutes. Each station is paired with the JPL station of the same kind nearest in time. Every station has a pair and the counts agree for every planet. The agreement is between two implementations of the same conventions, not a measure of how precise those conventions are; see Limits.
• When a planet passes almost exactly behind the Sun, the correction for the Sun’s bending of light can make the computed speed flip sign for up to about an hour. In Skyfield with DE440 this happens at about a dozen conjunctions of Jupiter, Uranus, Neptune and Pluto in the 201 years. A flip shorter than a day is an artefact, not a station, and both searches drop such pairs; a daily grid catches only a few of them (2 in this Skyfield run).

The script that produced every number on this page is published next to it as retrograde_periods.py. It needs Python 3 and pyswisseph; the JPL check also needs skyfield and the file de440s.bsp, and is skipped without them.

Limits

• Near a station a planet barely moves: for Neptune and Pluto the longitude changes by less than a second of arc in the day around it. The exact minute therefore depends on conventions. Pluto itself stations up to about 70 minutes away from the centre of mass of Pluto and Charon, and leaving out nutation (the small wobble of the Earth’s axis) would move the stations by up to about 50 minutes for Saturn, 2 hours for Uranus, 2½ hours for Neptune and 4 hours for Pluto. For the slow planets a station that falls within a few hours of midnight UT can land on the neighbouring date in another convention.
• Times are UT, for practical purposes the same as UTC or GMT. Future times rest on a forecast of the Earth’s rotation (ΔT), which by 2100 may be off by a minute or more; the two programs agreeing does not remove that. A station at 23:00 UT falls on the next day in Asia and Australia, one at 02:00 UT on the previous day in the Americas.
• Signs are tropical. In the sidereal (Lahiri) zodiac the same station falls about 24° earlier (from 22½° in 1900 to 25° in 2100), usually in the previous sign.
• Only the retrograde period itself is covered, from station to station. The “shadow” periods that some astrologers add before and after are not in the data; they can be derived from the station longitudes in the CSV.
• The numbers are astronomy: how often and how long the planets appear to move backwards. They say nothing about what a retrograde means for anyone.