24 Solar Terms · Harmony with Nature
The 24 Solar Terms form a time knowledge system created through observing the sun's annual movement
Summer · Fire
Autumn · Metal
Winter · Water
Solar Terms Encyclopedia
“Five days make a period. Three periods make a season. Six seasons make a year.” —Chronology of the Celestial Calendars
The Sun's Annual Trajectory
The 24 solar terms use the sun's position on the ecliptic as a measure, with each 15-degree interval marking one term, forming an orderly framework of seasons.
- Tropical year system: Dates are mostly fixed in the Gregorian calendar, with deviations no more than one or two days.
- Ecliptic longitude scale: Lichun 315°, Chunfen 0°, Xiazhi 90°, aligning spatial positioning with time measurement.
- Seasonal baseline: Four “Li” mark beginnings; equinoxes and solstices balance seasonal rhythm.
Five Days per Period · Three Periods per Term
The 72 pentads record subtle natural changes — thawing ice, birdsong, cicadas, frost. Each five-day span is a pentad; three pentads form a term, weaving the year's seasonal narrative.
- Fine observation: Highly granular records of nature, reflecting the linkage between organisms and climate.
- Winter Solstice example: First pentad earthworms knot; second pentad deer shed antlers; third pentad springs stir — signs of Yang energy rising.
- Daily guidance: Translating experience of observing sky, things, and water into coordinates for everyday actions.
Let Ancient Wisdom Resonate in the Cloud
With AI and data, phenological features become digital records to monitor climate shifts and deliver localized seasonal guidance by location — multilingual, cross-regional resonance.
- Precise calendrics: Astronomical algorithms capture the exact transit moments, ensuring rigorous order.
- Multi-dimensional aggregation: Structured content across wellness, folk customs, farming, and arts builds a knowledge graph.
- Transcending space and time: Multilingual versions and interactive experiences let global users perceive the beauty of the solar terms.