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Inner planets

How Mercury appears to move backwards

Mercury turns back three times a year, each time as it passes between Earth and the Sun. See how its fast inner orbit produces the backward stretch.

01 · The inner track

Mercury overtakes Earth on the inside.

Mercury circles the Sun in 88 days, inside Earth’s orbit. Every 116 days or so it passes between Earth and the Sun, at inferior conjunction. Around that pass, its fast motion on the near side of its orbit carries it the opposite way across our sky.

Mercury and Earth around the Sun, and Mercury’s position seen from Earth Left: Mercury on its inner orbit and Earth on its outer orbit around the Sun, seen from the north. A line from Earth through Mercury shows where Mercury appears. Right: its position against the stars over one 116-day cycle, with the backward stretch shaded. 9 days before inferior conjunction: Mercury is 16° east of the Sun, in the evening sky, moving backwards against the stars. SEEN FROM THE NORTH · SIZES NOT TO SCALE Earth · Mercury · Sun LONGITUDE SEEN FROM EARTH backwards 116 days, centred on inferior conjunction
9 days before inferior conjunctionMercury is 16° east of the Sun, in the evening sky, moving backwards against the stars.
Circular orbits at average speeds, seen from the north. The real orbit is noticeably elliptical, so real backward stretches last 20 to 24 days rather than this model’s 23.

Mercury moves backwards only around inferior conjunction, when it is between Earth and the Sun. Mars does the reverse, as why planets appear to move backwards shows: it moves backwards when Earth passes it, opposite the Sun.

02 · Mercury in 2026

Three backward stretches a year.

Because inferior conjunction comes about every 116 days, Mercury turns back three times in most years, occasionally four.

Mercury’s retrograde periods in 2026 Mercury moves backwards three times in 2026: from 26 February to 21 March, from 29 June to 24 July and from 24 October to 13 November, each about three weeks long and each centred near an inferior conjunction, on 7 March, 13 July and 4 November. MERCURY IN 2026 · SHADED: MOVING BACKWARDS JanFebMarAprMayJunJulAugSepOctNovDec 26 Feb to 21 Mar7 Mar29 Jun to 24 Jul13 Jul24 Oct to 13 Nov4 Nov Line: inferior conjunction
Station and conjunction dates from the site’s ephemeris, in IST, measured in the sidereal zodiac the site uses.

An inner planet

Mercury is the planet closest to the Sun. It orbits at about 0.39 times Earth’s distance and goes round in about 88 days, four times faster than Earth. Seen from Earth it therefore never strays far from the Sun: at most about 18° to 28° to one side, depending on where in its slightly elliptical orbit that greatest angle falls. It is seen only low in the twilight, after sunset when it is east of the Sun and before sunrise when it is west.

Overtaking on the inside

Most of the time Mercury moves forward along the ecliptic, eastward against the stars, like the Sun and the other planets. About every 116 days it passes between Earth and the Sun. This alignment is inferior conjunction.

Around that pass, Mercury is on the near side of its orbit, moving fast in the direction opposite to its motion on the far side. Seen from Earth, that carries it westward against the stars for a while. The backward stretch, retrograde motion, begins at one turning point, a station, and ends at another, with inferior conjunction near the middle.

The cause is the same as for Mars, a changing view from a moving Earth, but the arrangement is reversed. Mars, outside Earth’s orbit, moves backwards when Earth overtakes it on the inside, opposite the Sun. Mercury moves backwards when it overtakes Earth on the inside, in the Sun’s direction. Why planets appear to move backwards explains the outer-planet case.

Three times a year

Because inferior conjunction comes about every 116 days, Mercury turns back three times in most years and occasionally four. Each backward stretch lasts about three weeks: between 2026 and 2036, from 20 to 24 days. In 2026, measured in the sidereal zodiac, the dates are:

Turns back Inferior conjunction Turns forward
26 February 7 March 21 March
29 June 13 July 24 July
24 October 4 November 13 November

Times and exact dates come from the site’s ephemeris, in IST. Mercury moves very slowly for a day or two around each turning point, as what a station time means explains.

In a Kundli

A birth chart marks a planet moving backwards at the moment of birth with an R. For Mercury that happens for roughly a fifth of the year. The retrograde planets guide explains how the marking is read.

See Mercury’s next turning points on the planetary events page, or explore another topic in Learn.