This Wednesday, we had a culture class talking about the 24 Chinese solar terms. Teacher Vivian talked about the traditional sign of climate change.

The 24 solar terms, based on the sun’s position in the zodiac, were created by farmers in ancient China to guide the agricultural affairs and farming activities. The 24 solar terms reflect the changes in climate, natural phenomena, agricultural production, and other aspects of human life, including clothing, food, housing, and transportation. The 24 solar terms play important roles and have greatly influenced people’s basic needs in life, and they still have an important function nowadays.

The terms consist of 12 pairs of major (sectional) and minor (middle) solar terms interlaced with each other., namely.The 24 solar terms embody a complete circle of the sun and divide the circle into 24 segments, with each segment being about half a month long. In both the lunar and solar calendars, the Gregorian calendar date of each solar term is basically fixed, with minor differences of within one or two days.These solar terms have meaningful titles. Some of them reflect the change of seasons such as the Beginning of Spring, the Beginning of Summer, the Beginning of Autumn, and the Beginning of Winter; some embody the phenomena of climate like the Waking of Insects (Jing Zhe), Pure Brightness (Qing Ming), Lesser Fullness of Grain (Xiao Man) and Grain in Beard (Mang Zhong); and some indicate the change of climate like Rain Water (Yu Shui), Grain Rain (Gu Yu), Lesser Heat (Xiao Shu), Greater Heat (Da Shu), and so on.

So what are the 24 solar terms?

立春 the Beginning of Spring (1st solar term February 3-5)
雨水 Rain Water (2nd solar term February 18-20)
惊蛰 the Waking of Insects (3rd solar term March 5-7)
春分 the Spring Equinox (4th solar term March 20-22)
清明 Pure Brightness (5th solar term April 4-6)
谷雨 Grain Rain (6th solar term April 19-21)
立夏 the Beginning of Summer (7th solar term May 5-7)
小满 Grain Full (8th solar term May 20-22)
芒种 Grain in Ear (9th solar term June 5-7)
夏至 the Summer Solstice (10th solar term June 21-22)
小暑 Slight Heat (11th solar term July 6-8)
大暑 Great Heat (12th solar term July 22-24)
立秋 the Beginning of Autumn (13th solar term August 7-9)
处暑 the Limit of Heat (14th solar term August 22-24)
白露 White Dew (15th solar term September 7-9)
秋分 the Autumnal Equinox (16th solar term September 22-24)
寒露 Cold Dew (17th solar term October 8-9)
霜降 Frost’s Descent (18th solar term October 23-24)
立冬 the Beginning of Winter (19th solar term November 7-8)
小雪 Slight Snow (20th solar term November 22-23)
大雪 Great Snow (21st solar term December 6-8)
冬至 the Winter Solstice (22nd solar term December 21-23)
小寒 Slight Cold (23rd solar term January 5-7)
大寒 Great Cold (24th solar term January 20-21)

Meaning of the 24 Solar Terms
From the names of the 24 solar terms, we can see that the division of the solar terms has fully considered the variation of natural phenomena, such as seasons, climates and phenology.

The solar terms known as Start of Spring, Start of Summer, Start of Autumn, and Start of Winter are used to reflect the change of seasons, dividing the year into four seasons of exactly three months. While this fits an ideal pattern of dates, it does not reflect observable reality in most of China.

The solar terms of Vernal Equinox, Autumnal Equinox, Summer Solstice and Winter Solstice are divided from an astronomical aspect, reflecting the turning point of the variation of the altitude of the sun.

Clear and Bright, Rain Water, Grain Rain, Minor Snow, and Major Snow, White Dew, Cold Dew, and Frost Descent reflect the phenomenon of precipitation, indicating the time and intensity of rainfall, snowfall, dew, and frost.