What Are the Twenty-Four Solar Terms?

The Twenty-Four Solar Terms (èr shí sì jié qì) are a major invention of classical Chinese astronomy and calendrical science. They divide one tropical year (approximately 365.25 days) into twenty-four equal segments based on the sun’s apparent motion along the ecliptic, each segment lasting roughly fifteen days. They are not lunar months but nodes derived from the solar calendar (the sun’s apparent position). Twelve of these are called “nodes” (节 jié — Start of Spring, Awakening of Insects, Pure Brightness, etc.) and twelve are called “midpoints” (气 qì — Rain Water, Spring Equinox, Grain Rain, etc.), together forming the Twenty-Four Solar Terms.

The system can be traced back to the pre-Qin period, and by the time of the Huainanzi “Treatise on Astronomy” (《淮南子·天文训》), the full list of twenty-four names was already recorded. The ancients used these terms to guide agriculture, predict climate, and compile calendars. In Chinese metaphysics, the solar terms are the fundamental basis for temporal positioning in a life chart — without them, neither the year pillar nor the month pillar can be accurately determined.

How to Find the Solar Terms in Your Life Configuration

For a general reader, determining “which solar term applies to my chart” involves two main considerations: the starting point of the year pillar and the attribution of the month pillar.

Confirm your birth time in the Gregorian calendar: the more precise the year, month, day, and hour, the better.
Check the date of Start of Spring: find the exact day and minute of Start of Spring in your birth year (using a perpetual calendar or astronomical almanac). If you were born before Start of Spring, your year pillar belongs to the previous year; if after, it belongs to the current year.
Check the solar term for your birth month: each month pillar is led by a specific node — Start of Spring leads the Tiger month, Awakening of Insects leads the Rabbit month, Pure Brightness leads the Dragon month, and so on. Look up the exact moment of the node’s arrival for your birth month to determine the month pillar’s attribution.
The hour pillar does not require a solar term: it is derived solely from the birth hour and the day stem, and is not directly affected by solar terms.

The Four Pillars charting tool in unMing automatically calculates the year and month pillars based on precise solar term timings — no manual lookup is needed.

Types and Key Features of the Twenty-Four Solar Terms

The Twenty-Four Solar Terms can be classified in two ways: by the distinction between nodes and midpoints, and by seasonal attribution.

The Twelve “Nodes” and Twelve “Midpoints”

“Nodes” mark the turning points of the seasons — the odd-numbered twelve: Start of Spring, Awakening of Insects, Pure Brightness, Start of Summer, Grain in Ear, Minor Heat, Start of Autumn, White Dew, Cold Dew, Start of Winter, Major Snow, and Minor Cold. Nodes are the points at which the month pillar changes in a life chart. “Midpoints” mark climatic indicators within a season — the even-numbered twelve: Rain Water, Spring Equinox, Grain Rain, Grain Full, Summer Solstice, Major Heat, End of Heat, Autumn Equinox, Frost Descent, Minor Snow, Winter Solstice, and Major Cold. Midpoints primarily reflect climatic features and are not directly used for month-pillar changes.

Distribution by Season

The three months of spring (Tiger, Rabbit, Dragon) are led by Start of Spring, Awakening of Insects, and Pure Brightness, with Wood energy in command. The three months of summer (Snake, Horse, Goat) are led by Start of Summer, Grain in Ear, and Minor Heat, with Fire energy in command. The three months of autumn (Monkey, Rooster, Dog) are led by Start of Autumn, White Dew, and Cold Dew, with Metal energy in command. The three months of winter (Pig, Rat, Ox) are led by Start of Winter, Major Snow, and Minor Cold, with Water energy in command. The final months of each season — Dragon, Goat, Dog, and Ox — are the “four reservoirs,” where Earth energy is stored and in command.

Key Solar Terms and Their Metaphysical Significance

Among the twelve nodes, Start of Spring is the most critical — it marks the beginning of the entire year pillar (and thus the zodiac animal year). Next is Winter Solstice: the ancients regarded it as the day when yang energy begins to arise. In Chinese metaphysics, the concept that “yang energy is born at Winter Solstice” (冬至一阳生) influences judgments related to the “return of one yang” hexagram and seasonal transitions. Summer Solstice, conversely, marks the beginning of yin energy. The two solstices and two equinoxes (Spring Equinox, Summer Solstice, Autumn Equinox, Winter Solstice) together with the four starts (Start of Spring, Start of Summer, Start of Autumn, Start of Winter) are called the “Eight Nodes” (八节), the eight most important energy junctures of the year.

How the Solar Terms Shape Personality, Career, and Relationships

The solar terms themselves do not directly determine an individual’s personality, but they do determine the seasonal commander (月令 yuè lìng) — and the seasonal commander is one of the most powerful energy variables in a life configuration.

Personality

People born under different solar terms have different seasonal commander elements, and thus receive different seasonal energies. Those born in spring tend toward Wood energy, with a nature inclined to growth and expansion; those born in summer tend toward Fire energy, with an open and bright disposition; those born in autumn tend toward Metal energy, with a decisive character; those born in winter tend toward Water energy, with a deep and introspective temperament. This is a very basic level of constitutional tendency — the specifics must still be assessed in combination with the Day Master and the full chart.

Career

The seasonal commander — the energy of the solar term represented by the month branch — is the foundation for determining the structural configuration (格局 gé jú) and the Useful God (用神 yòng shén). The indirect influence of solar terms on career lies in their role as the starting point for assessing the Day Master’s strength or weakness: if the Day Master’s element is in harmony with the seasonal commander, it gains command (得令), which makes a significant difference. This, in turn, determines the basic direction for career strategy — whether to support the self, drain it, restrain it, or mediate.

Auspicious Day Selection and Major Life Cycles

Traditionally, important activities — weddings, groundbreaking ceremonies, business openings — avoid the three days before and after a solar term transition (known as the “Four Separations” and “Four Extremes” days). Chinese metaphysics and day selection share this lineage, holding that energy is unstable during solar term transitions and that major undertakings are inadvisable. While such applications are no longer widespread, they retain cultural reference value.

The Day Master’s Strength or Weakness

The solar terms directly determine whether the Day Master “gains command” from the seasonal commander — this is the first of the four major factors in assessing a strong or weak Day Master. A Jia Wood (yáng wood, 甲) Day Master born in the Tiger month (between Start of Spring and Awakening of Insects) gains command; one born in the Monkey month (between Start of Autumn and White Dew) loses command. This is not optional; it is the necessary starting point for any life-configuration analysis.

Classical Sources: The Solar Terms in the Canon

Growth in spring, development in summer, harvest in autumn, storage in winter — this is the constant way of heaven.
春生夏长，秋收冬藏，天道之常也。
— Guanzi “Explanation of Circumstances” (《管子·形势解》)

This passage uses the four processes — growth, development, harvest, and storage — to summarize the pattern of energy movement across the four seasons: spring governs growth, summer governs development, autumn governs harvest, and winter governs storage. The Twenty-Four Solar Terms are a further refinement of these four stages. In Chinese metaphysics, the seasonal flourishing of the Five Elements — Wood flourishes in spring, Fire in summer, Metal in autumn, Water in winter — is rooted in this principle.

The months have twelve establishments, with the solar terms as boundaries. Start of Spring establishes the Tiger month, Awakening of Insects establishes the Rabbit month, Pure Brightness establishes the Dragon month…
月有十二建，节气为界。立春建寅，惊蛰建卯，清明建辰……
— General calendrical principle across dynasties (see Huainanzi “Treatise on Astronomy,” etc.)

This is the doctrine of “month establishment” (月建). Each of the twelve months of the year is established with one of the twelve Earthly Branches, and the starting point is always the corresponding node. Once Start of Spring arrives, the Rat or Ox month ends and the Tiger month begins — at that point, the month pillar is established as Tiger. Chinese metaphysics inherits this method of month establishment, binding the solar terms to the Earthly Branches and giving chart construction a precise temporal basis. If one were to change the month pillar according to the lunar calendar’s first day instead of this method, the entire chart could be off by a month or a year.

Common Misconceptions About the Twenty-Four Solar Terms

A common error: treating the first day of the lunar new year as the point at which the year changes — “the New Year changes the zodiac animal.” In fact: in Chinese metaphysics, the boundary of the year pillar is Start of Spring, not New Year’s Eve or the first day of the lunar month. Start of Spring typically falls between February 3 and 5 in the Gregorian calendar. If someone is born in the first lunar month but before Start of Spring, their year pillar still belongs to the previous year, and their zodiac animal remains that of the previous year. Using “the New Year changes the zodiac animal” for chart construction can misplace the entire year pillar.

A common error: using the Gregorian calendar month directly to set the month pillar — “born in January means the Rat month.” In fact: the month pillar is determined by the solar terms and does not correspond one-to-one with Gregorian dates. A rough correspondence is: Tiger month (Feb 4–Mar 5), Rabbit month (Mar 6–Apr 4), Dragon month (Apr 5–May 5), and so on. But the exact moment of each solar term varies slightly from year to year; rigorous chart construction requires checking the specific node arrival time for that year.

A common error: treating the solar terms as weather forecasts — “Pure Brightness means it will rain,” “Start of Autumn means it will be cool.” In fact: the solar terms are astronomical markers based on the sun’s ecliptic longitude. Their names derive from long-term observed climatic patterns, but the actual weather in a given year and place may deviate from the average. The solar terms are long-term and statistical, not day-specific weather predictions; their function as energy nodes in Chinese metaphysics is independent of actual temperature.

Frequently Asked Questions

Does the zodiac animal change at the Chinese New Year?

This is the most common misunderstanding. In Chinese metaphysics, the boundary of the zodiac animal (the year branch) is Start of Spring, not the first day of the lunar new year. Start of Spring typically falls between February 3 and 5 in the Gregorian calendar. If the lunar new year has begun but Start of Spring has not yet arrived, people born on those days still belong to the previous year’s branch; only after Start of Spring does the new zodiac animal year truly begin. If one constructs a chart using “the New Year changes the zodiac animal,” the entire year pillar may be wrong.

Why is the month pillar based on the node rather than the lunar month?

The month branch represents the “seasonal commander” — the energy of heaven and earth at that time. This energy is determined by the solar terms: when Awakening of Insects arrives, the Tiger month ends and the Rabbit month begins, rather than changing on the first day of the lunar month. The solar terms correspond to the actual position of the sun along the ecliptic, which is synchronized with the earth’s actual climatic rhythm; the lunar month incorporates the moon’s phases and lacks the precision needed for energy changes.

Do the solar terms affect the day pillar and hour pillar?

The stems and branches of the day pillar and hour pillar are not determined by the solar terms — they are calculated by the continuous cycle of the sixty-sexagenary cycle, with the day pillar changing each day and the hour pillar changing every two hours. However, the solar terms do affect the Day Master’s strength within the life configuration: if the Day Master’s element “gains command” in the month corresponding to a given solar term (e.g., a Jia Wood Day Master born in the Tiger, Rabbit, or Dragon month gains command), this is the first step in assessing a strong or weak Day Master.

What are the Twenty-Four Solar Terms?

The twelve nodes and twelve midpoints together make twenty-four. The nodes: Start of Spring, Awakening of Insects, Pure Brightness, Start of Summer, Grain in Ear, Minor Heat, Start of Autumn, White Dew, Cold Dew, Start of Winter, Major Snow, Minor Cold. The midpoints: Rain Water, Spring Equinox, Grain Rain, Grain Full, Summer Solstice, Major Heat, End of Heat, Autumn Equinox, Frost Descent, Minor Snow, Winter Solstice, Major Cold. In chart construction, the twelve nodes are critical — they are the points at which the month pillar changes.

If I was born on the day of a solar term transition, how do I determine which month I belong to?

A solar term transition has a precise minute-level timing. If your birth time is before the node, you still belong to the previous month pillar; if after the node, you belong to the next month pillar. Rigorous chart construction requires checking the exact moment of that year’s node (which can be calculated by astronomical algorithms), rather than simply relying on the Gregorian date. The unMing tool automatically handles this conversion.

See Your Solar Terms in unMing

The Four Pillars charting tool in unMing calculates your year and month pillars based on precise solar term timings. After charting, you will see: the year pillar is determined by Start of Spring — if you were born on February 3, 2000 (the day before Start of Spring), your year pillar is still Ji Mao (the 1999 stem-branch pair), not Geng Chen. The month pillar is determined by the node corresponding to your birth month — if you were born before Awakening of Insects, you belong to the Tiger month; if after, to the Rabbit month. Observing whether the seasonal commander’s element in your chart is in harmony with the Day Master is the first step in assessing a strong or weak Day Master.