Mercury Retrograde 2026 - Dates & Timings

Three times a year, maybe four.

Mercury swings inside Earth's orbit, moving faster than we do. As it overtakes us, its apparent motion through the zodiac reverses—backward for about three weeks. Then forward again. This isn't metaphysical speculation. Pure geometry.

Earth takes 365 days to circle the Sun. Mercury completes its lap in 88 days. So Mercury laps Earth multiple times per year. Each pass triggers a retrograde. The pattern repeats: roughly every four months, Mercury appears to slow, stop, reverse, stop again, resume.

Ancient astronomers tracked this. Called it vakragati—curved motion. Sūrya Siddhānta gives the model: retrograde begins when Mercury's longitudinal speed crosses zero. No guessing. Direct observation, precise calculation.

The ancients got it right without telescopes. Naked-eye tracking over decades. The math still works.

Mercury retrogrades more than any other visible planet. Three to four times a year. Each period lasts about three weeks. The timing shifts annually but follows a rhythm.

Because Mercury orbits so close to the Sun, it never appears far from sunrise or sunset. Ancient observers tracked its evening and morning appearances. When it disappeared behind the Sun, then reappeared on the other side, they knew retrograde had occurred.

Per classical astronomy, Mercury's retrograde starts when its apparent speed becomes negative. That's the rule. The planet's longitudinal velocity crosses zero—forward motion becomes backward.

Modern ephemeris software uses NASA JPL planetary data (DE440/441 series), the same calculations guiding spacecraft navigation. Apply Lahiri Ayanāṃśa to align with the sidereal zodiac used in Jyotish. The result matches ancient observations within seconds.

Cross-reference against historical records. Check planetary tables from different traditions—Babylonian, Greek, Indian, Islamic. They converge. The sky doesn't lie.