Six periods across the two years. Every date below was computed by the same ephemeris that runs the Celestial Sextant app — not copied from another site's table — and the method (and its measured error) is written out under the table.
The periods
Times are UTC. "Begins" is the retrograde station — the moment Mercury's apparent motion reaches zero and turns backwards — and "ends" is the direct station, where forward motion resumes. The shadow period is the full span in which Mercury crosses the same stretch of zodiac three times: it starts when Mercury first reaches the degree it will later station direct on, and ends when, after turning direct, it passes the degree it stationed retrograde on.
| Retrograde begins | Retrograde ends | Days | Signs involved | Shadow period |
|---|---|---|---|---|
| Thu 26 Feb 2026 06:48 UTC · 22°34′ Pisces |
Fri 20 Mar 2026 19:32 UTC · 8°29′ Pisces |
22.5 | Pisces | Wed 11 Feb 2026 → Thu 09 Apr 2026 |
| Mon 29 Jun 2026 17:35 UTC · 26°15′ Cancer |
Thu 23 Jul 2026 22:57 UTC · 16°19′ Cancer |
24.2 | Cancer | Sat 13 Jun 2026 → Fri 07 Aug 2026 |
| Sat 24 Oct 2026 07:12 UTC · 20°59′ Scorpio |
Fri 13 Nov 2026 15:53 UTC · 5°02′ Scorpio |
20.4 | Scorpio | Sun 04 Oct 2026 → Mon 30 Nov 2026 |
| Tue 09 Feb 2027 17:36 UTC · 5°59′ Pisces |
Wed 03 Mar 2027 12:32 UTC · 20°55′ Aquarius |
21.8 | Pisces → Aquarius | Mon 25 Jan 2027 → Tue 23 Mar 2027 |
| Thu 10 Jun 2027 18:15 UTC · 6°22′ Cancer |
Sun 04 Jul 2027 19:39 UTC · 27°28′ Gemini |
24.1 | Cancer → Gemini | Wed 26 May 2027 → Mon 19 Jul 2027 |
| Thu 07 Oct 2027 14:37 UTC · 4°56′ Scorpio |
Thu 28 Oct 2027 14:10 UTC · 19°19′ Libra |
21.0 | Scorpio → Libra | Fri 17 Sep 2027 → Sat 13 Nov 2027 |
Mercury is retrograde for roughly three weeks, three times a year — 67.1 days in total across 2026 and 66.8 across 2027 by these stations, a little under a fifth of each year.
What it actually is
Mercury never actually reverses its orbit. Retrograde is what its motion looks like from a moving Earth: as Mercury swings around the far side of its fast inner orbit and passes between the Earth and the Sun, the line of sight from here sweeps backwards against the background stars for a few weeks — the same effect as watching a slower car appear to drift backwards as you overtake it, except Mercury is the faster one and we are watching from the overtaken lane.
The stations in the table are the two moments in each cycle where that apparent motion passes through zero. They are ordinary, precisely predictable geometry, known to the minute years in advance.
Astrological tradition treats Mercury retrograde as a period for review rather than launch: re-reading, repairing, and finishing things, with extra care around messages, contracts, and travel plans. That is a tradition, not a measurement, and this page makes no claim that retrograde Mercury causes delays, misunderstandings, or anything else.
What we can stand behind is the astronomy above: if you follow the tradition, the least we can do is give you dates that are computed properly, with their workings shown.
How these dates were computed
These dates come from Celestial Sextant's own ephemeris: the VSOP87D planetary theory (the subset built into the app), with light-time, aberration, nutation and an era-based ΔT correction applied — the code path in the project's ephemeris.ts / vsop87.ts. A station is a root of Mercury's apparent ecliptic-longitude speed: the scan sampled the speed every six hours across 2025–2028 and refined each sign change by bisection. The shadow boundaries are the two extra crossings of the station longitudes, found the same way. As a cross-check, the daily station scan the app's own transit module uses flags the same six stations.
How good is the engine? The app measures itself against the Swiss Ephemeris and publishes the residuals: for Mercury the worst measured difference across the app's test epochs is 0.3 arcseconds of longitude, inside its 5-arcsecond tolerance band. That is the accuracy story behind every chart the calculator casts — you can read the full residuals, free, in the app's Accuracy & caveats panel.
One honest limit: dates and times here are UTC, as the engine computes in Universal Time. An evening station in UTC can fall on the previous or next local date depending on where you live.
Your chart, not just the calendar
Cast your natal chart free and see Mercury's sign, house, and whether it was retrograde when you were born — computed on your device, no account, and your birth data never leaves it.