☿ Mercury

Mercury governs thinking and speech — how you process and explain. It spends about 30.3 days in each sign and takes 1 years to go round the zodiac, so its sign changes fast enough to differ between people born days apart.

Speed decides what it can tell you

Mercury stays 30.3 days in a sign

30.3 days per sign — the window in which everyone shares this placement.
1 years for a full circuit of the twelve signs.
Personal Fast enough to differ between siblings.

Because it moves quickly, this placement genuinely separates one chart from another — which is why the birth time and date both matter. Work out your own chart →

How often it turns back

Mercury goes retrograde every 0.32 years

116 days between one retrograde and the next — the synodic period, the time it takes to line up with Earth again.
0.32 years between loops. That does not divide evenly into a calendar year, so the dates drift and some years have none at all.
Apparent not real. Nothing reverses direction — Earth overtakes on the inside of the track and the planet appears to slide backwards against the stars.

Communication, travel, contracts, devices and everything that has to be re-read is what the tradition attaches to it, and the retrograde is read as that turning inward. The motion itself is a perspective effect and has been understood as one since Copernicus. Every Mercury retrograde by year →

Mercury in each sign

in Aries in Taurus in Gemini in Cancer in Leo in Virgo in Libra in Scorpio in Sagittarius in Capricorn in Aquarius in Pisces

Other planets

☉ Sun ☽ Moon ♀ Venus ♂ Mars ♃ Jupiter ♄ Saturn ♅ Uranus ♆ Neptune ♇ Pluto