The 24 Solar Terms: A BaZi Calendar Primer

The twenty-four solar terms cut the sun’s year into arcs of about fifteen days. BaZi uses twelve of them, the section terms, to open the twelve month branches, and uses Start of Spring to open the year pillar as well. The other twelve terms are midpoints: they matter in seasonal language and in festivals, and they do not flip the month pillar. This primer is professional calendar guidance for reading a chart, not a personality system.

Key facts

Section terms open the months: Start of Spring, Awakening of Insects, Clear and Bright, Start of Summer, Grain in Ear, Slight Heat, Start of Autumn, White Dew, Cold Dew, Start of Winter, Major Snow, and Minor Cold.
Midpoint terms include the solstices and equinoxes, Rain Water, Grain Rain, Grain Full, Major Heat, Limit of Heat, Frost Descent, Minor Snow, and Major Cold. They fall inside a month that has already opened.
Start of Spring opens both the tiger month and the BaZi year. Lunar new year and 1 January do not.
A term is an instant, then a local clock. The civil date can differ by time zone. The Gregorian month name is not the pillar.
The day-officer cycle used in date selection is a third calendar. It is not one of the twenty-four terms.
None of the terms schedules surgery, a filing, or a contract. They locate pillars.

Twelve doors and twelve pauses

Think of the year as twelve rooms. Each room is an earthly branch, about thirty days, and the door is a section term. Start of Spring opens the tiger. Awakening of Insects opens the rabbit. Clear and Bright opens the dragon. Start of Summer opens the snake. Grain in Ear opens the horse. Slight Heat opens the goat. Start of Autumn opens the monkey. White Dew opens the rooster. Cold Dew opens the dog. Start of Winter opens the pig. Major Snow opens the rat. Minor Cold opens the ox, which runs until the next Start of Spring. If you remember only the doors, you can already catch a chart that followed the Western month instead.

The pauses are the midpoint terms, traditionally called qi as against the section jie. Spring equinox sits inside the rabbit month. Summer solstice sits inside the horse month. Autumn equinox sits inside the rooster month. Winter solstice sits inside the rat month. They are famous because daylight changes, and because several cultures built festivals there. Fame does not promote them to doors. A person born the day after the summer solstice is still in the horse month if Grain in Ear has already opened it and Slight Heat has not yet come. The month pillar’s connection is that rule in detail. This page is the map the rule sits on.

Names you will see in English

Translations drift. Grain in Ear, Corn on the Ear, and Grain in Beard are one term. Slight Heat and Minor Heat are one term. Major Snow and Great Snow are one term. The Chinese name on a careful chart is the anchor. The English is a gloss. When two websites seem to list different terms, check whether they split a translation or actually moved a door. The count must remain twenty-four, alternating door and pause, beginning at Start of Spring in the order above.

Seasonal nicknames such as “early spring” are not terms. Qixi, the double-seventh festival, is a lunar date and not a solar term at all, which is why Qixi does not decide a chart. Qingming as a festival clusters near the Clear and Bright term and still should not be used as a mood in place of the minute.

What the primer is for when you read a chart

The primer answers a sorting question. Given a birth date, which door had most recently opened, in that city, at that clock. The answer is the month branch. The year branch is the door of Start of Spring, not the nearest festival. What BaZi is builds the four pillars on that sorting. Four pillars then give each pillar a job. Without the doors, the month job is guesswork and the strength of the day master is guesswork after it.

You do not need to recite all twenty-four to use a chart. You need to notice birthdays that fall near a door: the 4th through the 8th of many months, and the first week of February for the year as well. Those dates are suspects. Mid-month birthdays are usually quiet. Suspect does not mean unlucky. It means look up the minute instead of trusting the month printed on a form. Birthdays near a term is the procedure. Time zones are why the minute in Dubai is not the minute in Chicago.

A May form that says the wrong animal-month

A reader in Boston fills a coaching intake on Monday at 10:00 and writes “May, so snake month,” because a social post said summer’s snake begins when May begins. Start of Summer, the door of the snake, falls around 5 to 7 May, not on 1 May. A birth on 2 May is still in the dragon month opened at Clear and Bright in early April, unless that particular year’s minute says otherwise, which it will not by several days. The intake at 10:00 is a conversation. It does not move Start of Summer. If the coach casts a snake month from the word May, the season, the structure, and the useful-element sketch are aimed at the wrong room.

The correction is the primer, not a debate about personality. Look up which door had opened. Dragon and snake are neighbors and still different commands: earth storage versus fire’s season. BaZi is built to use the door. A primer that you apply by hand is only a check on nonsense, not a second engine. The guidance disclaimer still holds: the right month is guidance about climate, not a diagnosis delivered at 10:00.

What to memorize

Memorize the difference between a door and a pause, the name of the door that also opens the year, and the habit of suspecting birthdays near the 4th to the 8th. Look up everything else in the chart rather than in a rhyme. Rhymes round to the day. Pillars move on the minute. Lunar festivals, however beloved, are a different instrument and a different article.

The light chart shows the month the doors produced. The full chart adds layers that assume the month is already right. The full chart cannot repair a month taken from a Western calendar. Help explains the pages. Pick a Good Day uses its own day cycle for ranking dates. It is not a twenty-four-term recital, and it should not be asked to stand in for one.

What this is not

Not a claim that all twenty-four terms change the month pillar. Only the twelve section terms open months.
Not a lunar calendar, a Gregorian month, or the twelve day officers.
Not a list of lucky or unlucky fortnights.
Not medical timing, agricultural advice for a specific field, or a contract calendar.
Not a personality type for each term.
Not entertainment. The terms are how this guidance keeps a calendar.