二十四节气
24 Solar Terms
Chinese Philosophy · conceptThe 24 solar terms (二十四节气) are a traditional Chinese calendar system that divides the solar year into 24 periods of approximately 15 days each, based on the sun's position in the zodiac. Formalized during the Han dynasty and recorded in the Huainanzi (139 BCE), each term reflects seasonal changes in climate, agriculture, and natural phenomena. The system was declared a UNESCO Intangible Cultural Heritage in 2016. Unlike the lunar calendar, solar terms are based on the tropical year — the same astronomical foundation as the Western calendar.
Context and Boundaries
The solar terms are based on the sun's position along its apparent annual path and on the tropical year, not on the moon's phases; the traditional Chinese calendar is lunisolar, which is the usual source of the confusion. The Hong Kong Observatory publishes the official explanation of this sun-position basis, and it is used here for the astronomical basis only. The system was formalized during the Han dynasty and recorded in the Huainanzi (139 BCE), in the astronomical chapter (Tian Wen Xun) where the full written list of the 24 term names appears; the exact year the text was presented to court is not asserted as settled here. In 2016 UNESCO inscribed the system on the Representative List of the Intangible Cultural Heritage of Humanity under the name "The Twenty-Four Solar Terms, knowledge in China of time and practices developed through observation of the sun's annual motion."
What this does not establish: The solar terms are a solar (tropical-year) system, not a lunar one. Their "guiding agriculture and daily life" description is a seasonal-calendar claim, not an individualized weather or crop forecast, and no individual term carries a guaranteed health, personality, fortune, or agricultural-yield prediction for any person or place. Approximate calendar windows are reading aids; exact instants are deferred to astronomical tables, and no fixed longitude value or fixed date list is asserted here. Each of the 24 terms has its own per-term page and card; this page covers the system rather than the individual terms, and it does not treat the registered per-term card relationships as confirmed.
A restrained present-day reading: Oriens interpretation: the 24 solar terms can be read as an early, careful way of organizing a year by observation of the sun — a calendar built to keep human time aligned with the seasons rather than with the moon. That is an interpretive framing, not a claim that the terms predict anything, and not a guarantee of any agricultural, health, or personal outcome.
The 24 solar terms divide the year according to the sun's position, guiding agriculture and daily life.
— Huainanzi, Chapter 3 (Liu An)
What Are the Key Facts About 24 Solar Terms?
- Tradition: Chinese Philosophy
- Chinese: 二十四节气
- Category: Concept
- Definition: The 24 solar terms (二十四节气) are a traditional Chinese calendar system that divides the solar year into 24 periods of approximately 15 days each, based on the sun's position in the zodiac.
What Cards Are Related to 24 Solar Terms?
Spring Begins
The year turns toward warmth
Rain Water
The ice softens into rain
Awakening of Insects
Thunder stirs the sleeping world
Spring Equinox
Day and night stand as equals
Pure Brightness
Clear skies, clear hearts
Grain Rain
The last rain of spring feeds the seedlings
Summer Begins
The sun climbs to its throne
Grain Full
The kernels swell with promise
Grain in Ear
The awns emerge, the harvest nears
Summer Solstice
The longest day, the turning point
Minor Heat
The warmth becomes weight
Major Heat
The year's hottest breath
Autumn Begins
The first leaf turns
End of Heat
The last warmth releases its grip
White Dew
Morning moisture turns to pearl
Autumn Equinox
Balance returns, then tips toward night
Cold Dew
The chill arrives with the morning
Frost Descent
The first ice claims the ground
Winter Begins
The earth closes its doors
Minor Snow
The first flakes drift down
Major Snow
The world goes white and silent
Winter Solstice
The darkest day, the returning light
Minor Cold
The chill deepens before the thaw
Major Cold
The final freeze before spring
Frequently Asked Questions About 24 Solar Terms
What are the 24 Solar Terms?
The 24 Solar Terms (jieqi) are a traditional Chinese calendar dividing the year by astronomical and climatic markers (e.g., Spring Equinox, Grain Rain, Major Heat) to guide agriculture.
How were they developed?
Originating in the Yellow River basin over 2000 years ago, they track the sun's position (15 degrees per term) and were inscribed on UNESCO's Intangible Heritage list in 2016.
Are they still used?
Yes — they remain culturally central in China for farming, festivals, and food, and mark seasonal customs and health (diet) advice.
How do they relate to Chinese philosophy?
They embody the yin-yang and Five Phases worldview: time as a rhythmic, cyclical process of qi's transformation through the year.
Where to Read Next
- What Is Solar Terms?The longer definition, the 二十四节气 meaning, and the significance of the system.
- Solar Terms Complete GuideHow the system works, the moon-vs-sun distinction, the major/minor split, UNESCO, and the 24-term reference table.
- 24 Solar Terms ReferenceThe dates and reference family (approximate windows, not fixed dates).
- Solar Term LìchūnThe first per-term guide owner (Start of Spring).
- Solar Term DōngzhìThe winter-solstice per-term guide owner.
- Solar Term Card 001 — Spring BeginsThe first per-term card.
- Solar Term Card 024 — Major ColdThe final per-term card.
Sources and Limits
- Hong Kong Observatory — The 24 Solar TermsSun-position basis and astronomical convention
- UNESCO Intangible Cultural Heritage — The Twenty-Four Solar Terms2016 inscription, official element name
- Chinese Text Project — Huainanzi, Tian Wen XunChapter 3, Han-era written list of the 24 term names