What is Mercury retrograde?
Mercury retrograde is the stretch of about three weeks when Mercury appears to move backward through the zodiac, as seen from Earth. Mercury never really reverses. Earth and Mercury circle the Sun at different speeds, and when Mercury passes Earth on its inside track, it seems to slow down, stop and drift backward against the stars.
The moment Mercury seems to stand still and turn is called a station. It stations retrograde at the start and stations direct at the end.
The shadow before and after
Before it turns retrograde, Mercury moves forward over the degrees it will soon cover backward. That approach is the pre-shadow. After it turns direct, it covers the same degrees a third time, and the post-shadow lasts until it passes the point where it first turned. Many astrologers read the pre-shadow as the time when themes first appear and the post-shadow as the time when they settle.
What it means in astrology
Mercury rules communication, thinking, paperwork, short trips and technology. While it is retrograde, astrology reads these areas as better suited to review than to fresh starts. Plans may need a second look, messages a second reading and schedules some slack. It is also a good time for anything with “re” in it: revising, repairing, reconnecting with people and finishing what you started.
How we calculate it
Mercury’s position is computed from NASA JPL’s DE440 ephemeris. Each station is the exact moment Mercury’s motion along the zodiac reverses, and each shadow boundary is the moment Mercury crosses the degree of the opposite station. Times are shown in your local time zone.
Frequently asked questions
- How long does Mercury retrograde last?
- About three weeks. With the pre-shadow before it and the post-shadow after it, the whole cycle runs close to two months.
- How often does Mercury go retrograde?
- Usually three times a year, and in some years a fourth retrograde begins. Mercury catches up with Earth on the inside track roughly every four months.
- What is the Mercury retrograde shadow?
- The shadow is the stretch of the zodiac Mercury covers three times. The pre-shadow begins when Mercury first reaches the degree where it will later turn direct, and the post-shadow ends when it passes the degree where it turned retrograde.
- What should I do during Mercury retrograde?
- Use it to review rather than rush: reread messages before sending them, double-check plans and bookings, back up your files and give delays a little extra room. It is a good time to finish, revise and reconnect.
- Why do Mercury retrograde dates differ between sites?
- Many sites list only a date for a moment that falls on different calendar days around the world, and some define the shadow loosely. This page shows the exact moment of each station in your own time zone.