Introduction of the Twenty-Four Solar Terms and the Seventy-Two Pentads: Spring
✵Four Seasons, Eight Solar Terms, Twenty-Four Solar Terms, and the Seventy-Two Pentads in Spring, Summer, Autumn, and Winter are introduced. The Four Seasons, Eight Solar Terms, Twenty-Four Solar Terms, and Seventy-Two Pentads system is a traditional Chinese calendar system established in ancient China.
This part introduces the climate characteristics of the spring and its corresponding solar terms, as well as the health risks associated with seasonal factors and preventive measures.
Characteristics of the Spring Climate and Health Risks
Spring is the first of the four seasons. Climatologically, it refers to the period when the average temperature over a "hou" (a five-day period) ranges from 10 °C to 22 °C. Spring includes six solar terms: the Beginning of Spring, Rain Water, Awakening from Hibernation, the Spring Equinox, Pure Brightness, and Grain Rain.
In spring, the Northern Hemisphere of the Earth begins to tilt toward the Sun, receiving increasing amounts of sunlight; thus, temperatures begin to rise. As a result, ice and snow melt and river water levels rise; plants begin to sprout and grow, and many flowers bloom; hibernating animals awaken, and egg-laying animals hatch; birds begin to migrate from their wintering grounds to their breeding grounds; and many animals enter estrus—all of which fill us with delight.
However, as spring returns to the Earth and all things come to life, some pathogenic microorganisms also revive and are carried by the wind. Taking advantage of this, they enter the body and affect health or trigger illness. According to the Five Elements theory of Traditional Chinese Medicine, wind pathogens are particularly prevalent in spring. Since wind is considered the “leader of all pathogens,” it easily combines with other pathogenic factors to invade the body and cause disease. Therefore, health preservation in spring cannot be ignored.
Solar terms in Spring:
1. The solar term "Lichun" (the Beginning of Spring) is the first solar term among the twenty-four solar terms of the traditional Chinese lunisolar calendar. It is defined astronomically as the moment when the Sun reaches a celestial longitude of 315°, occurring annually on February 3rd or 4th. Lichun is one of China’s important traditional seasonal markers—not a festival per se, though it has long been observed ceremonially. "Li" means "beginning"; since the Qin Dynasty, an official tradition had formed designating Lichun as the astronomical and cultural start of spring. As the saying goes, “The plan for the year begins with spring”: temperatures rise, flowers begin to bloom, birds resume singing, and farmers commence plowing and sowing.
2. The solar term "Yushui" (Rain Water) is the second of the twenty-four solar terms. It usually falls around the 15th day of the first lunar month (Gregorian calendar: February 18–19), when the Sun reaches a celestial longitude of 330°. At this time, temperatures continue to rise, snow and ice melt, and precipitation increases—hence the name “Rain Water.” Yushui begins on February 18th or 19th and lasts until March 4th or 5th. As its name indicates, this solar term reflects the marked increase in rainfall.
3. The solar term "Jingzhe" (Awakening from Hibernation) is the third of the twenty-four solar terms, occurring around March 5th or 6th, when the Sun reaches a celestial longitude of 345°. Before Jingzhe, hibernating insects and small animals remain dormant underground—neither eating nor drinking—hence the character 蛰 (zhé), meaning "to hibernate." The character 惊 (jīng), meaning "to startle" or "awaken," refers to the spring thunder that rouses them from dormancy. During Jingzhe, temperatures warm significantly, spring thunderstorms occur, and most regions of China—and the Northern Hemisphere broadly—enter the peak plowing season.
4. "Chunfen" (the Spring Equinox, also known as the Vernal Equinox) marks the midpoint of spring—the 90-day period between Lichun and Lixia. It is the fourth solar term, occurring annually around March 20th or 21st, when the Sun crosses the celestial equator and reaches 0° celestial longitude.
On the day of the Spring Equinox, the Sun shines directly over Earth’s equator. Because the Northern and Southern Hemispheres experience opposite seasons, this day is the Spring Equinox in the Northern Hemisphere but the Autumnal Equinox in the Southern Hemisphere. The Spring Equinox is also the traditional New Year in several countries.
In calendrical usage, "Spring Equinox" may also refer to the 15-day period during which the Sun travels from 0° to 15° celestial longitude—that is, from the equinox day itself to the onset of the next solar term, Qingming (Pure Brightness). In the Gregorian calendar, this spans approximately March 20 to April 5.
On the equinox day, day and night are nearly equal in length worldwide. After the Spring Equinox, the subsolar point moves northward across the equator; thus, days grow longer and nights shorter in the Northern Hemisphere, while the reverse occurs in the Southern Hemisphere.
5. "Qingming" (Pure Brightness), also known as Tomb-Sweeping Day, is the fifth solar term, occurring annually around April 4th to 6th, when the Sun reaches a celestial longitude of 15°. Qingming is both a solar term and a major traditional Chinese observance—a time for ancestral veneration and tomb-sweeping. Originating in the Zhou Dynasty over 2,500 years ago, it was officially designated a national public holiday in 1935 and is sometimes called the National Tomb-Sweeping Festival. As the name suggests, Qingming signifies clarity and brightness: skies clear, scenery brightens, and nature flourishes. Temperatures continue to rise, marking the full onset of spring agricultural activity.
6. "Guyu" (Grain Rain) is the sixth solar term, occurring around April 19th to 21st, when the Sun reaches a celestial longitude of 30°. Ancient texts state, "Rain nourishes the grains"—hence the name. Guyu marks the optimal period for sowing seeds, planting trees, and cultivating beans. During Guyu, temperatures rise rapidly, and rainfall becomes frequent across the Northern Hemisphere.
References:
1. Introduction of the Twenty-Four Solar Terms and the Seventy-Two Pentads: Spring
2. Yi Zhou Shu (the Lost Book of the Zhou Dynasty)
Spring is the first of the four seasons. Climatologically, it refers to the period when the average temperature over a "hou" (a five-day period) ranges from 10 °C to 22 °C. Spring includes six solar terms: the Beginning of Spring, Rain Water, Awakening from Hibernation, the Spring Equinox, Pure Brightness, and Grain Rain.
1. The solar term "Lichun" (the Beginning of Spring) is the first solar term among the twenty-four solar terms of the traditional Chinese lunisolar calendar. It is defined astronomically as the moment when the Sun reaches a celestial longitude of 315°, occurring annually on February 3rd or 4th. Lichun is one of China’s important traditional seasonal markers—not a festival per se, though it has long been observed ceremonially. "Li" means "beginning"; since the Qin Dynasty, an official tradition had formed designating Lichun as the astronomical and cultural start of spring. As the saying goes, “The plan for the year begins with spring”: temperatures rise, flowers begin to bloom, birds resume singing, and farmers commence plowing and sowing.
2. The solar term "Yushui" (Rain Water) is the second of the twenty-four solar terms. It usually falls around the 15th day of the first lunar month (Gregorian calendar: February 18–19), when the Sun reaches a celestial longitude of 330°. At this time, temperatures continue to rise, snow and ice melt, and precipitation increases—hence the name “Rain Water.” Yushui begins on February 18th or 19th and lasts until March 4th or 5th. As its name indicates, this solar term reflects the marked increase in rainfall.
3. The solar term "Jingzhe" (Awakening from Hibernation) is the third of the twenty-four solar terms, occurring around March 5th or 6th, when the Sun reaches a celestial longitude of 345°. Before Jingzhe, hibernating insects and small animals remain dormant underground—neither eating nor drinking—hence the character 蛰 (zhé), meaning "to hibernate." The character 惊 (jīng), meaning "to startle" or "awaken," refers to the spring thunder that rouses them from dormancy. During Jingzhe, temperatures warm significantly, spring thunderstorms occur, and most regions of China—and the Northern Hemisphere broadly—enter the peak plowing season.
4. "Chunfen" (the Spring Equinox, also known as the Vernal Equinox) marks the midpoint of spring—the 90-day period between Lichun and Lixia. It is the fourth solar term, occurring annually around March 20th or 21st, when the Sun crosses the celestial equator and reaches 0° celestial longitude.
On the day of the Spring Equinox, the Sun shines directly over Earth’s equator. Because the Northern and Southern Hemispheres experience opposite seasons, this day is the Spring Equinox in the Northern Hemisphere but the Autumnal Equinox in the Southern Hemisphere. The Spring Equinox is also the traditional New Year in several countries.
In calendrical usage, "Spring Equinox" may also refer to the 15-day period during which the Sun travels from 0° to 15° celestial longitude—that is, from the equinox day itself to the onset of the next solar term, Qingming (Pure Brightness). In the Gregorian calendar, this spans approximately March 20 to April 5.
5. "Qingming" (Pure Brightness), also known as Tomb-Sweeping Day, is the fifth solar term, occurring annually around April 4th to 6th, when the Sun reaches a celestial longitude of 15°. Qingming is both a solar term and a major traditional Chinese observance—a time for ancestral veneration and tomb-sweeping. Originating in the Zhou Dynasty over 2,500 years ago, it was officially designated a national public holiday in 1935 and is sometimes called the National Tomb-Sweeping Festival. As the name suggests, Qingming signifies clarity and brightness: skies clear, scenery brightens, and nature flourishes. Temperatures continue to rise, marking the full onset of spring agricultural activity.
6. "Guyu" (Grain Rain) is the sixth solar term, occurring around April 19th to 21st, when the Sun reaches a celestial longitude of 30°. Ancient texts state, "Rain nourishes the grains"—hence the name. Guyu marks the optimal period for sowing seeds, planting trees, and cultivating beans. During Guyu, temperatures rise rapidly, and rainfall becomes frequent across the Northern Hemisphere.
