What Are the 24 Solar Terms?
The 24 Solar Terms (二十四節氣, 24절기, nijūshisekki) are a system of dividing the solar year into 24 equal segments of 15 degrees of the sun's ecliptic longitude. Originating in ancient China over 2,000 years ago, they are used across East Asia to mark seasonal transitions and guide agricultural activities.
In 2016, UNESCO inscribed the 24 Solar Terms on the Intangible Cultural Heritage list as a "Chinese practice of observing the Sun's annual motion."
The Four Groups
The 24 terms are organized around the four cardinal solar events:
- Solstices and Equinoxes (4): Vernal Equinox (춘분), Summer Solstice (하지), Autumnal Equinox (추분), Winter Solstice (동지)
- Agricultural terms (20): Terms marking planting, rain, heat, harvest, and cold periods
The Full List (with Korean names)
- 입춘(立春) — Start of Spring (Feb 4) | 우수(雨水) — Rain Water (Feb 19)
- 경칩(驚蟄) — Awakening of Insects (Mar 6) | 춘분(春分) — Vernal Equinox (Mar 21)
- 청명(清明) — Clear and Bright (Apr 5) | 곡우(穀雨) — Grain Rain (Apr 20)
- 입하(立夏) — Start of Summer (May 6) | 소만(小滿) — Grain Buds (May 21)
- 망종(芒種) — Grain in Ear (Jun 6) | 하지(夏至) — Summer Solstice (Jun 21)
- 소서(小暑) — Minor Heat (Jul 7) | 대서(大暑) — Major Heat (Jul 23)
- 입추(立秋) — Start of Autumn (Aug 7) | 처서(處暑) — End of Heat (Aug 23)
- 백로(白露) — White Dew (Sep 8) | 추분(秋分) — Autumnal Equinox (Sep 23)
- 한로(寒露) — Cold Dew (Oct 8) | 상강(霜降) — Frost's Descent (Oct 23)
- 입동(立冬) — Start of Winter (Nov 7) | 소설(小雪) — Minor Snow (Nov 22)
- 대설(大雪) — Major Snow (Dec 7) | 동지(冬至) — Winter Solstice (Dec 22)
- 소한(小寒) — Minor Cold (Jan 6) | 대한(大寒) — Major Cold (Jan 20)
Cultural Significance in Korea
In Korea, solar terms are deeply woven into food culture and daily life:
- 입춘: "입춘대길(立春大吉)" signs are posted on doors for good luck
- 동지: Red bean porridge (팥죽) is eaten to ward off evil spirits
- 경칩: Traditionally when frogs awaken; a cue to begin spring farming
- 삼복(三伏): The three hottest days (초복·중복·말복) around 소서/대서; samgyetang (삼계탕) is eaten
Why Solar Terms Are Precise
Unlike lunar calendar dates, solar terms have fixed astronomical definitions — they do not drift against the seasons. This made them essential for agricultural planning even in lunisolar calendar systems, where the month dates could vary. They represent one of humanity's oldest and most elegant solutions to the problem of seasonal coordination.