☿ Mercury Combustion 2026

2026 has six Mercury cazimis: three with Mercury on the far side of the Sun (superior conjunctions) and three with Mercury between Earth and the Sun (inferior conjunctions, each in the middle of a retrograde).

One more combustion touches the year without its cazimi falling in it: December 17, 2026 to January 15, 2027. It is listed too.

Each card gives the moments Mercury comes within 8°30′ of the Sun and leaves again, the exact cazimi and its degree, the hours Mercury spends within 17′, and the reading for the sign it meets the Sun in.

Mercury's orbit lies inside Earth's, so from here it swings from one side of the Sun to the other and back. Each round brings two conjunctions. In the superior one Mercury is beyond the Sun, 1.32 to 1.45 astronomical units (AU) from Earth, moving forward through the signs. In the inferior one it passes between Earth and the Sun, only 0.55 to 0.68 AU away, moving backward: every Mercury retrograde has an inferior conjunction in its middle.

Medieval and early modern astrologers, William Lilly among them, counted combustion among the worst accidental debilities a planet can have and cazimi among the best. For Mercury, the significator of speech, writing, bargaining, contracts and short trips, combustion is read as messages that do not land as meant and papers signed without a careful reading, with the picture clearing once Mercury moves out of the beams.

The two kinds are not read the same way. A superior combustion has Mercury moving forward at its fastest; an inferior one adds the backtracking of the retrograde, which is why it is usually read as the harder of the two.

Between 2025 and 2035 Mercury has 35 superior and 34 inferior combustions. The inferior ones last 7 to 11 days, the superior ones 14 to 30. The length is set by how fast Mercury and the Sun separate, since the combust zone is 17° wide (8°30′ on each side).

At an inferior conjunction Mercury is retrograde, moving against the Sun, so the two close and separate at 1.52° to 2.4° a day and the crossing is quick. At a superior conjunction they move the same way, Mercury only 0.56° to 1.25° a day faster, so on average the pass takes 2.3 times as long.

The superior passes also vary with the season. The three longest in the data, with cazimis on December 11, 2027 (30 days), December 2, 2034 (30 days) and November 20, 2028 (29 days), come with Mercury 0.46 to 0.47 AU from the Sun, near the far end of its stretched orbit, where it moves slowest. The shortest, nine passes of 14 days each, all have the cazimi between April 28 and July 19, with Mercury 0.31 to 0.32 AU from the Sun, near the close end of its orbit, where it moves fastest.

All 69 combustions with a cazimi in these years, grouped by that year. "Path" is the degree where Mercury enters the 8°30′ zone and the degree where it leaves. In a superior combustion the path runs forward through the zodiac; in every inferior one it runs backward, from a later degree to an earlier one, because Mercury is retrograde.

A cazimi is exact in longitude, so the gap along the zodiac is zero at the listed moment. Mercury's orbit is tilted against Earth's, though, so at that moment it usually passes north or south of the Sun. At the inferior conjunctions in the data it misses the Sun's center by 0°09′ to 4°58′; at the superior ones by 0°01′ to 2°04′, less because Mercury is then much farther from us.

Only when the miss is smaller than the Sun's apparent radius, 15.7′ to 16.3′ depending on the time of year, does Mercury line up with the disk. At an inferior conjunction that is a transit: Mercury crosses the face of the Sun as a small dark dot, visible only through a telescope with a proper solar filter. The data has one, on November 13, 2032, at 09:08 UTC, with Mercury 0°09′ north of the center. Most astrologers judge cazimi by longitude alone, as this page does, whatever the latitude.

At three superior conjunctions Mercury passes behind the disk instead, hidden by the Sun itself: May 14, 2026, May 7, 2033 and November 12, 2035.

Mercury spends 89 to 114 days of each year combust, 27% of all the days from 2025 to 2035. The years with seven cazimis (2027, 2029 and 2033) are the ones where the cycle, 116 days on average from one superior conjunction to the next, fits an extra conjunction in before December 31.

Every Mercury retrograde in these years has an inferior conjunction in its middle. Mercury turns retrograde, reaches the Sun 9 to 14 days later, and turns direct 9 to 14 days after that. In every case the combust stretch lies wholly inside the retrograde, so the first and last days of a Mercury retrograde are never combust days.

The superior combustions never touch a retrograde. Their cazimi comes 33 to 58 days after Mercury turns direct and 33 to 58 days before it turns retrograde again.

Astrologers who read combustion as concealment and retrograde as going back over things treat the overlap as the quietest part of the retrograde for Mercury matters: the days to read, check and correct rather than to announce.

Natal Mercury combustion is common. Mercury is within 8°30′ of the Sun on 27% of the days from 2025 to 2035, so about one person in four is born with it. A common traditional reading is a mind that serves the will: quick to argue for what the person already wants, slower to question it. Modern astrologers often add that such people think best alone and show their ideas finished rather than in drafts.

A natal cazimi is far rarer. Mercury spends only about 0.8% of the time within 17′ of the Sun, and astrologers read that placement the other way round: the Sun lends Mercury its strength, and speech and identity work as one.

To check your own chart, compare the degrees of the Sun and Mercury in the birth chart calculator. Within 17′ is cazimi, within 8°30′ combust, within 17° under the beams.

Positions come from our ephemeris: geocentric, apparent, in the tropical zodiac. A program steps through every year, finds each moment Mercury's longitude comes within 8°30′ of the Sun's and the moment it moves back out, narrows each crossing to the second, and takes the cazimi as the moment the two longitudes are equal. A second pass recomputes every period from scratch and checks it against the first.

Separation is measured along the ecliptic only, which is the usual practice and why the gap at every cazimi reads 0.0′ in the cards. Under the beams means within 17°; cazimi means within 17′. Dates written in sentences are UTC dates; the cards and tables switch to your time zone. The method page lists every convention the site's calculations follow.