Mercury
Mercury orbits the Sun in 87.97 days, inside Earth’s orbit, and turns retrograde about every 116 days, when it passes between Earth and the Sun. Mercury is direct, inside the shadow before its next retrograde, which begins on 24 Oct 2026 at 20°58′ Scorpio.
Mercury’s orbit drawn from above the Sun, one tick a day along it. The two dashed lines mark the furthest the planet can stand from the Sun as seen from Earth where Earth is now; at its greatest elongations it reaches between 17.9° and 27.6°, depending on where Earth and the planet are on their orbits. On 16 Oct 2026 it is 24.7° east of the Sun, an evening object, setting after the Sun. Orbits are drawn flat in the ecliptic plane; elongations are angles on the sky. The ring is the zodiac at infinity: the marked longitude is carried out from the Sun parallel to the sight line, because the line itself meets the finite ring at a shifted point.
Orbit
- Sidereal period
- 87.97 days
- Synodic period
- 115.88 days
- Mean distance from the Sun
- 0.387 AU
- Next perihelion
- 0.308 AU · 10 Nov 2026
- Next aphelion
- 0.467 AU · 24 Dec 2026
- Eccentricity
- 0.206
- Inclination to the ecliptic
- 7.0°
- Greatest elongation, next 6 years
- 17.9 – 27.6°
- Retrogrades per year (mean)
- 3.15
- Length of the listed retrogrades
- 21 – 25 days
The sidereal period is astronomy-engine’s mean orbital period for the planet; the synodic period and retrograde rate follow from it and Earth’s. The next perihelion and aphelion (true distance from the Sun), greatest elongations and retrograde lengths are computed from the ephemeris; retrograde lengths count calendar days from station to station, both included. Mean distance, eccentricity and inclination are from NASA’s Planetary Fact Sheet.
Why it reverses
Faster on the inside track.
Mercury completes an orbit in 87.97 days, Earth in 365 days. About every 116 days Mercury passes between Earth and the Sun. Then it is moving across our line of sight faster than Earth is moving around, so from here it appears to slide backward against the stars.
The reversal is bracketed by two stations, days when Mercury seems to stand still. In the windows listed below, retrograde lasts 21 – 25 days (calendar days, both stations included) and retraces 8.6 – 16.2° of the zodiac.
Retrogrades, 2025 to 2028
| Station R | Station D | Sign | Stations | Arc | Days |
|---|---|---|---|---|---|
| 9 Nov 2025 | 29 Nov 2025 | Sagittarius → Scorpio | 6°51′ Sagittarius → 20°42′ Scorpio | 16.1° | 21 |
| 26 Feb 2026 | 20 Mar 2026 | Pisces | 22°33′ → 8°29′ Pisces | 14.0° | 23 |
| 29 Jun 2026 | 23 Jul 2026 | Cancer | 26°15′ → 16°19′ Cancer | 9.9° | 25 |
| 24 Oct 2026 | 13 Nov 2026 | Scorpio | 20°58′ → 5°02′ Scorpio | 15.9° | 21 |
| 9 Feb 2027 | 3 Mar 2027 | Pisces → Aquarius | 5°58′ Pisces → 20°55′ Aquarius | 15.0° | 23 |
| 10 Jun 2027 | 4 Jul 2027 | Cancer → Gemini | 6°21′ Cancer → 27°28′ Gemini | 8.8° | 25 |
| 7 Oct 2027 | 28 Oct 2027 | Scorpio → Libra | 4°55′ Scorpio → 19°18′ Libra | 15.6° | 22 |
| 24 Jan 2028 | 14 Feb 2028 | Aquarius | 19°41′ → 3°59′ Aquarius | 15.7° | 22 |
| 21 May 2028 | 14 Jun 2028 | Gemini | 16°18′ → 7°45′ Gemini | 8.5° | 25 |
| 19 Sep 2028 | 11 Oct 2028 | Libra | 18°35′ → 3°28′ Libra | 15.1° | 23 |
Computed from the ephemeris and checked against NASA JPL Horizons; times UTC. As data: JSON · Markdown · how the dates are computed
Mercury retrograde by sign: Aries · Taurus · Gemini · Cancer · Leo · Virgo · Libra · Scorpio · Sagittarius · Capricorn · Aquarius · Pisces
In the sources
What was written about Mercury turning back.
| Date | Source | Planets | Kind |
|---|---|---|---|
| c. 652–61 BCE | Astronomical DiariesAnonymous (Babylonian scribes)Observation | Me Ve Ma Ju Sa | Observation |
| c. 380–50 BCE | Babylonian planetary ephemeridesAnonymous (Babylonian scribes)Math. astronomy | Me Ve Ma Ju Sa | Math. astronomy |
| c. 350–330 BCE | Metaphysics Λ.8AristotleTheory / model | Me Ve Ma Ju Sa | Theory / model |
| 3rd–1st centuries BCE | Goal-Year TextsAnonymous (Babylonian scribes)Observation | Me Ve Ma Ju Sa | Observation |
| c. 2nd–1st century BCE (debated); reconstruction 2021 | Antikythera Mechanism: Front Cover InscriptionAnonymous (Greek makers)Math. astronomy | Me Ve Ma Ju Sa | Math. astronomy |
Mercury retrograde, answered
How often does Mercury go retrograde?
About every 116 days — its synodic period, the time Mercury takes to lap Earth — which comes to three or four retrogrades a calendar year. In 2026 it stations retrograde on 26 Feb, 29 Jun and 24 Oct.
How long does Mercury retrograde last?
21 to 25 days for the retrogrades from 2025 to 2028, counting both station days. The next one runs from 24 Oct 2026 to 13 Nov 2026, 21 days; with its shadow on either side the episode lasts 58 days, 4 Oct 2026 to 30 Nov 2026.
Why does Mercury appear to move backward?
Mercury orbits inside Earth's orbit and faster. About every 116 days it passes between Earth and the Sun; around that moment it is moving across our line of sight faster than Earth is, so against the stars it appears to slow, stop, slide backward and stop again before resuming. Nothing about its orbit reverses — only the direction we see it in.
How far from the Sun does Mercury get?
At greatest elongation Mercury stands between 17.9° and 27.6° from the Sun over the next 6 years; the spread comes from its eccentric orbit, which brings it much nearer the Sun at perihelion than at aphelion. The next greatest elongations: 20 Nov 2026, 19.6° west (morning); 3 Feb 2027, 18.3° east (evening); 17 Mar 2027, 27.6° west (morning); 28 May 2027, 22.9° east (evening).
When can you see Mercury?
Low in the twilight around its greatest elongations — after sunset when it stands east of the Sun, before sunrise when it stands west. The next morning elongation is on 20 Nov 2026 (19.6°); the next evening elongation is on 3 Feb 2027 (18.3°). Around inferior conjunction, in the middle of each retrograde, and around superior conjunction it is lost in the Sun's glare. On 16 Oct 2026 it is 24.7° east of the Sun, an evening object, setting after the Sun.
Station alerts
A heads-up before every turn.
An email 3 days before the shadow and each station, one when it turns retrograde, and an all‑clear when it goes direct. Plus a note on each Mercury cazimi.