The 24 solar terms

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  • Location: China

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., namelyThe 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.

24 solar terms map

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.

Minor Heat, Major Heat, Limit of Heat, Minor Cold, and Major Cold reflect the changes of temperature in different periods.

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.

Small Full (Grain) and Grain in Ear reflect the maturity and harvest time of crops, while Awakening of Insects reflects observed insect activity.

Origin

As early as the Spring and Autumn Period (770–476 BC), Chinese ancestors had already established two major solar terms, ri nan zhi (日南至 'Sun South Most') and ri bei zhi (日北至 'Sun North Most').

As of the end of the Warring States Period (475–221 BC), eight key solar terms (Start of Spring, Vernal Equinox, Start of Summer, Summer Solstice, Start of Autumn, Autumnal Equinox, Start of Winter and Winter Solstice) marking the four seasons, were established according to the different positions of the sun and changes in natural phenomena.

The rest of the solar terms were initiated in the Western Han Dynasty (206 BC–24 AD). Hence most terms refer to the climate of Xi'an, capital of the Han Dynasty.

List of the 24 Solar Terms in 2014

Solar Terms 

Chinese

Month and Date

Remarks

Start of Spring

lì chūn
立春

Feb 4th

A dubiously premature name, as it's not the beginning of spring in most of China; only in the extreme south.

Rain Water

yǔ shuǐ
雨水

Feb 19th

There is an increase of rainfall from then on.

Awakening of Insects

jīng zhé
惊蛰

Mar 6th

Thunder begins and hibernating insects wake up.

Vernal Equinox

chūn fēn
春分

Mar 21st

With an equal length of day and night.

Clear and Bright

qīng míng 清明

Apr 5th

It is clear and bright (when it's not raining), and the weather becomes noticeably warmer. A misnomer, particularly in southern China.

Grain Rain

gǔ yǔ
谷雨

Apr 20th

The early crops show their shoots.

Start of Summer

lì xià
立夏

May 5th

The beginning of summer (in southern China).

Small Full (Grain)

xiǎo mǎn
小满

May 21st

The seeds of summer crops begin to become plump, but are not yet ripe.

Grain in Ear

máng zhǒng 芒种

Jun 6th

The wheat becomes ripe; and the summer planting starts (in southern China).

Summer Solstice

xià zhì
夏至

Jun 21st

The daytime is the longest and the nighttime is the shortest of the year.

Minor Heat

xiǎo shǔ
小暑

Jul 7th

The beginning of the hottest period. 

Major Heat

dà shǔ
大暑

Jul 23rd

It is the time of year when the duration of the sunshine is the longest, the average temperature is the highest, the rainfall is the greatest, and the thunderstorms are the most frequent (in some parts of northern China).

Start of Autumn

lì qiū 立秋

Aug 7th


An anomaly: nowhere is this true. Like the "start of spring" it is about a month premature.

Limit of Heat

chù shǔ 处暑

Aug 23rd

The end of the hot summer.

White Dew

bái lù 白露

Sep 8th

The transition from summer to autumn. The temperature drops sharply, and the autumn rains come.

Autumnal Equinox 

qiū fēn 秋分

Sep 23rd

With an equal length of day and night.

Cold Dew

hán lù 寒露

Oct 8th

The weather becomes cold enough to reach dew point, but not cold enough to reach frost point.

Frost Descent

shuāng jiàng 霜降

Oct 23rd

The weather becomes cold and frost begins to form (in North China).

Start of Winter

lì dōng 立冬

Nov 7th

True of northern China, but winter comes later in the south.

Minor Snow

xiǎo xuě 小雪

Nov 22nd

Snow begins to fall, the weather becomes cold.

Major Snow

dà xuě 大雪

Dec 7th

It snows heavily for the first time in the year (in northern China).

Winter Solstice

dōng zhì 冬至

Dec 22nd

The daytime is the shortest and the nighttime is the longest of the year.

Minor Cold

xiǎo hán 小寒

Jan 5th

The weather rapidly reaches its coldest.

Major Cold

dà hán 大寒

Jan 20th

'Major Cold' It is the coldest time of the year.

Further Reading