A guiding principle in teaching is: tell them what you’re going to teach them, teach it, review what you just taught. Repetition. By repeating something three times, it sinks in. You get the message across.

Mercury operates the same way. It goes around the sun three times for every one earth orbit. It passes between earth and the sun three times in every year, creating three retrograde cycles. And in each retrograde cycle, it makes a series of three aspects to one or more slow planets, and usually a series of three aspects to planets in any given natal chart. In this way, Mercury the Messenger gets his message across.

The three Mercury retrograde cycles in the period of a year (not necessarily a “man-made” calendar year) are often in the same element, since there are three signs in each of the four elements, and they are about a third of the sky apart. Frequently, there’s a repetition of a portion of the degree ranges in these three signs. Thus, three consecutive Mercury retrograde cycles may aspect a particular slow planet or a planet in a natal chart. Now, the message is blaring!

For instance, in 2021, the three Mercury retrograde cycles occur in Air signs.
January 15 – March 13 in Aquarius between 11 and 26 degrees (Rx 1/30 – 2/20)
May 14 – July 7 in Gemini between 16 and almost 25 degrees (Rx 5/29 – 6/22)
Sept. 6 – Nov. 2 in Libra between 10 and 25 degrees (Rx 9/27 – 10/18)

These dates cover the full time span from the entry of Mercury into the range of degrees across which it actually backtracks to its exit from the range. The time frame of reverse motion (Rx) is shorter. Note how the degrees between 16 and 24+ are covered in each cycle. If there is a slow planet traveling in that degree range in a sign affected by major aspects from Air signs, it receives three hits from Mercury three times, for a total of nine in a year – talk about repetition! Planets in Air and Fire signs qualify for such emphasis.

In some one-year periods, all the Mercury retrogrades are in the same element. On either side of this, there will be years in which the Mercury retrograde range zigzags between adjacent signs of two different elements. The next year might be all in the new element. The degree positions of the retrograde ranges shift lower in the zodiac from year to year: the retrogrades themselves retrograde.

Again, using a three-year span, we see:
2020 Mercury retrogrades in Water signs or Water signs shifting to Air signs
2021 Mercury retrogrades all in Air signs
2022 Mercury retrogrades in Air signs shifting to Earth signs

Typically, there is a slight overlap in the date ranges from one year’s Mercury retrogrades to the next. It’s usually just a few days, six or so, from the beginning of the earlier year’s span to the end of the next year’s. Here’s an example:
2020 autumn retrograde 10/13 – 11/3
2021 autumn retrograde 9/27 – 10/18 (repeating prior year’s 10/13 – 10/18)
2022 autumn retrograde 9/9 – 10/2 (repeating prior year’s 9/27 – 10/2)
Because of this overlap, you can have Mercury retrograde at two birthdays in a row, an extended period for learning and re-learning certain lessons or to make and reiterate your points.

The only slow planet traveling in 2021’s repeated Mercury retrograde sites (in an Air or Fire sign, thus receiving major aspects from the Air signs in which Mercury retrogrades) is the dwarf planet Eris at 23-24 degrees of Aries. The only possible major aspects between planets traveling in two different elements of the same polarity (such as Fire and Air both being “masculine” signs) are trines, sextiles or oppositions. (Conjunctions would occur in the same element; squares do not occur between compatible elements.) Mercury is sextile Eris in the winter and spring retrogrades of 2021 and opposite Eris in the autumn. In researching for his book on Eris’s influence in U.S. history (Yankee Doodle Discord), Thomas Canfield discovered that Eris behaves with more chaos and difficulty in the “soft” aspects, such as the sextile, and has a more positive expression in the “hard” aspects, such as the opposition. This little powerhouse planet likes to spur conflict. In mythology, Eris entered the battlefield with her brother Mars and delighted in seeing people fight, not caring which side they were on.

Eris seems to be playing a part in the current climate of conflict and divisiveness in the U.S. It’s in the process of making a series of squares to U.S. natal Mercury at 24 degrees of Cancer. Eris aspects are generally four to five years in duration and have nine or, more frequently, eleven hits. We can’t even agree on facts and information (Mercury’s turf). And we seem to keep having the same arguments over and over, a “curse” of our natal Mercury being retrograde! Eris makes eleven squares to U.S. Mercury from 2019 to 2024, covering two consecutive presidential election primary seasons. If you thought the past campaign was vicious, wait until the next one. Eris is not all bad, though. She has a great respect for truth. Perhaps the force of these squares will help shake and wake the portion of the populace suffering under delusions to see reality. Dates for the squares depend on the exact location of natal Mercury, and since it’s a quick planet and there is no definitive birth time for the U.S. on July 4, 1776, it’s not possible to pinpoint specific dates.

In addition, this year’s three Mercury Retrogrades all strongly aspect the U.S. natal Mars at 21 degrees of Gemini. The Aquarius Mercury retrograde was trine the U.S. Mars, as the Libra Mercury retrograde will be, and the Gemini Mercury retrograde is conjunct it. The June 10 solar eclipse aimed a big spotlight at U.S. Mars, too. The Moon and Sun at almost 20 degrees of Gemini were less than two degrees away from U.S. Mars and retrograde Mercury at almost 21 degrees of Gemini was about half a degree away. This fires up our ire and raises the stakes. The dates of Mercury’s conjunctions to U.S. Mars (exact times depending on which U.S. birth time is used) are 5/19-20, 6/9 and 7/3-4 – yes, right at our birthday. Having this aspect at our solar return will stretch its affects out over the coming year. Expect the heated arguments to continue.

Adding confusion to its current retrograde cycle, Mercury makes three squares to transiting Neptune (exact on 5/22, 6/5 and 7/6). Neptune is already exceptionally foggy during its twelve-year movement through the sign it rules (between 2012 and- 2025). Some characteristics of Neptune in Pisces easily seen at this time are: sensitivity to suffering, including feelings of mistreatment; focus on health care systems (and their shortcomings); secrets and people who lie or intentionally misconstrue situations or can’t tell truth from fiction, e.g., the conspiracy theories running rampant. There are positive expressions, as well, such as increased sympathy and the realization of our interconnectedness with all people and life on our planet. Faith and beliefs are under the purview of this planet/sign pair, too, and for good or ill, religious tenets are seeping their way into many aspects of our experience and discussions.

Mercury often presents the same (or similar) information or situations to us over and over until we get the message or see things from a different angle. It’s all part of Mercury as the teacher, repeating the lesson again and again.