Solar term

The 24 solar terms
(Twenty-four) solar terms
Traditional Chinese(二十四)節氣
Simplified Chinese(二十四)节气
Solar term
Term Longitude Dates
Lichun 315° 4–5 February
Yushui 330° 18–19 February
Jingzhe 345° 5–6 March
Chunfen 20–21 March
Qingming 15° 4–5 April
Guyu 30° 20–21 April
Lixia 45° 5–6 May
Xiaoman 60° 21–22 May
Mangzhong 75° 5–6 June
Xiazhi 90° 21–22 June
Xiaoshu 105° 7–8 July
Dashu 120° 22–23 July
Liqiu 135° 7–8 August
Chushu 150° 23–24 August
Bailu 165° 7–8 September
Qiufen 180° 23–24 September
Hanlu 195° 8–9 October
Shuangjiang 210° 23–24 October
Lidong 225° 7–8 November
Xiaoxue 240° 22–23 November
Daxue 255° 7–8 December
Dongzhi 270° 21–22 December
Xiaohan 285° 5–6 January
Dahan 300° 20–21 January

A solar term (or jieqi, simplified Chinese: 节气; traditional Chinese: 節氣) is any of twenty-four periods in traditional Chinese lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon. The points are spaced 15° apart along the ecliptic and are used by lunisolar calendars to stay synchronized with the seasons, which is crucial for agrarian societies. The solar terms are also used to calculate intercalary months; which month is repeated depends on the position of the sun at the time.

According to the Book of Documents, the first determined term was Dongzhi (Winter Solstice) by Dan, the Duke of Zhou, while he was trying to locate the geological center of the Western Zhou dynasty, by measuring the length of the sun's shadow on an ancient type of sundial called tǔguī [ja] (土圭). Then four terms of seasons were set, which were soon evolved as eight terms; until 104 BC in the book Taichu Calendar, the entire twenty-four solar terms were officially included in the Chinese calendar.

Because the Sun's speed along the ecliptic varies depending on the Earth-Sun distance, the number of days that it takes the Sun to travel between each pair of solar terms varies slightly throughout the year, but it is always between 15 and 16 days. Each solar term is divided into three pentads [zh] (; hòu), so there are 72 pentads in a year. Each pentad consists of five, rarely six, days, and are mostly named after phenological (biological or botanical) phenomena corresponding to the pentad.

Solar terms originated in China, then spread to Korea, Vietnam, and Japan, countries in the East Asian cultural sphere. Although each term was named based on the seasonal changes of climate in the North China Plain, peoples living in the different climates still use it without changes. This is exhibited by the fact that traditional Chinese characters for most of the solar terms are identical.

On December 1, 2016, the solar terms were listed by UNESCO as an Intangible Cultural Heritage.

Numbering

The even solar terms (marked with "Z", for Chinese: 中氣) are considered the major terms, while the odd solar terms (marked with "J", for Chinese: 節氣) are deemed minor. The year starts with Lichun (J1) and ends with Dahan (Z12).

Multilingual list

Sun's ecliptic
longitude
Chinese
name
Korean name Vietnamese
name
Japanese
name
Ryukyuan
(Okinawan) name
English
name
English
name (Beijing 2022 Winter Olympics official translation)
Gregorian
Date
(± 1 day)
Reference for
Month Intercalating
Chinese zodiac & Earthly Branch of Month Corresponding Western astrological sign
315° 立春
lìchūn
立春 (입춘/립춘)
ipchun/ripchun
Lập xuân (立春) 立春(りっしゅん)
risshun
立春(りっしゅん)
risshun
Spring commences Beginning of Spring Feb 4 1st month initial Tiger ()
Yín ()
Aquarius
330° 雨水
yǔshuǐ
雨水 (우수)
usu
Vũ thủy (雨水) 雨水(うすい)
usui
雨水(うしー)
ushii
Rain water Rain Water Feb 19 1st month midpoint Pisces
345° 驚蟄 (惊蛰)
jīngzhé
驚蟄 (경칩)
gyeongchip
Kinh trập (驚蟄) 啓蟄(けいちつ)
keichitsu

驚く(うどぅるく)
uduruku;
驚くー(おどるくー)
udurukuu;
虫驚(むしうどぅるく)
mushi'uduruku

Insects waken Awakening of Insects Mar 6 2nd month initial Rabbit ()
Mǎo ()
春分
chūnfēn
春分 (춘분)
chunbun
Xuân phân (春分) 春分(しゅんぶん)
shunbun
春分(すんぶん)
sunbun
Vernal equinox Spring Equinox Mar 21 2nd month midpoint Aries
15° 清明
qīngmíng
淸明 (청명)
cheongmyeong
Thanh minh (清明) 清明(せいめい)
seimei
清明(しーみー)
shiimii
Bright and clear Pure Brightness Apr 5 3rd month initial Dragon ()
Chén ()
30° 穀雨 (谷雨)
gǔyǔ
穀雨 (곡우)
gogu
Cốc vũ (穀雨) 穀雨(こくう)
kokuu
穀雨(くくー)
kukuu
Corn rain Grain Rain Apr 20 3rd month midpoint Taurus
45° 立夏
lìxià
立夏 (입하/립하)
ipha/ripha
Lập hạ (立夏) 立夏(りっか)
rikka
立夏(りっかー)
rikkaa
Summer commences Beginning of Summer May 6 4th month initial Snake ()
()
60° 小滿 (小满)
xiǎomǎn
小滿 (소만)
soman
Tiểu mãn (小滿) 小満(しょうまん)
shōman
小満(すーまん)
suuman
Corn forms Grain Buds May 21 4th month midpoint Gemini
75° 芒種 (芒种)
mángzhòng
芒種 (망종)
mangjong
Mang chủng (芒種) 芒種(ぼうしゅ)
bōshu
芒種(ぼーすー)
boosuu
Corn on ear Grain in Ear Jun 6 5th month initial Horse()
()
90° 夏至
xiàzhì
夏至 (하지)
haji
Hạ chí (夏至) 夏至(げし)
geshi
夏至(かーちー)
kaachii
Summer solstice Summer Solstice Jun 21 5th month midpoint Cancer
105° 小暑
xiǎoshǔ
小暑 (소서)
soseo
Tiểu thử (小暑) 小暑(しょうしょ)
shōsho
小暑(くーあちさ)
kuu'achisa
Moderate heat Minor Heat Jul 7 6th month initial Goat ()
Wèi ()
120° 大暑
dàshǔ
大暑 (대서)
daeseo
Đại thử (大暑) 大暑(たいしょ)
taisho
大暑(うーあちさ)
uu'achisa
Great heat Major heat Jul 23 6th month midpoint Leo
135° 立秋
lìqiū
立秋 (입추/립추)
ipchu/ripchu
Lập thu (立秋) 立秋(りっしゅう)
risshū
立秋(りっすー)
rissuu
Autumn commences Beginning of Autumn Aug 8 7th month initial Monkey ()
Shēn ()
150° 處暑 (处暑)
chǔshǔ
處暑 (처서)
cheoseo
Xử thử (處暑) 処暑(しょしょ)
shosho
処暑(とぅくるあちさ)
tukuru'achisa
End of heat End of Heat Aug 23 7th month midpoint Virgo
165° 白露
báilù
白露 (백로)
baekno/baekro
Bạch lộ (白露) 白露(はくろ)
hakuro
白露(ふぁくるー)
fakuruu
White dew White Dew Sep 8 8th month initial Rooster ()
Yǒu ()
180° 秋分
qiūfēn
秋分 (추분)
chubun
Thu phân (秋分) 秋分(しゅうぶん)
shūbun
秋分(すーぶん)
suubun
Autumnal equinox Autumn Equinox Sep 23 8th month midpoint Libra
195° 寒露
hánlù
寒露 (한로)
hanlo
Hàn lộ (寒露) 寒露(かんろ)
kanro
寒露(かんるー)
kanruu
Cold dew Cold Dew Oct 8 9th month initial Dog ()
()
210° 霜降
shuāngjiàng
霜降 (상강)
sanggang
Sương giáng (霜降) 霜降(そうこう)
sōkō
霜降(しむくだり)
shimukudari
Frost Frost's Descent Oct 23 9th month midpoint Scorpio
225° 立冬
lìdōng
立冬 (입동/립동)
ipdong/ripdong
Lập đông (立冬) 立冬(りっとう)
rittō
立冬(りっとぅー)
rittuu
Winter commences Beginning of Winter Nov 7 10th month initial Pig ()
Hài ()
240° 小雪
xiǎoxuě
小雪 (소설)
soseol
Tiểu tuyết (小雪) 小雪(しょうせつ)
shōsetsu
小雪(くーゆち)
kuuyuchi
Light snow Minor Snow Nov 22 10th month midpoint Sagittarius
255° 大雪
dàxuě
大雪 (대설)
daeseol
Đại tuyết (大雪) 大雪(たいせつ)
taisetsu
大雪(うーゆち)
uuyuchi
Heavy snow Major Snow Dec 7 11th month initial Rat ()
()
270° 冬至
dōngzhì
冬至 (동지)
dongji
Đông chí (冬至) 冬至(とうじ)
tōji
冬至(とぅんじー)
tunjii
Winter solstice Winter Solstice Dec 22 11th month midpoint Capricorn
285° 小寒
xiǎohán
小寒 (소한)
sohan
Tiểu hàn (小寒) 小寒(しょうかん)
shōkan
小寒(すーかん)
suukan
Moderate cold Minor Cold Jan 6 12th month initial Ox ()
Chǒu ()
300° 大寒
dàhán
大寒 (대한)
daehan
Đại hàn (大寒) 大寒(だいかん)
daikan
大寒(でーかん)
deekan
Severe cold Major Cold Jan 20 12th month midpoint Aquarius

Chinese mnemonic song

The "Song of Solar Terms" (simplified Chinese: 节气歌; traditional Chinese: 節氣歌; pinyin: jiéqìgē) is used to ease the memorization of jieqi:

The first four lines provides a concise version of the names of the 24 jieqi. The last four lines provide some rules of thumb about the Gregorian dates of jieqi, namely:

  • Two jieqi per month;
  • Gregorian dates are off by one or two days at most;
  • In the first half of the year, jieqi happens around the 6th and 21st day of each (Gregorian) month;
  • In the second half of the year, jieqi happens around the 8th and 23rd day of each (Gregorian) month.

Determination

Chart with the solar terms and their Vietnamese names

The modern definition using ecliptic longitudes, introduced by the Shixian calendar, is known as 定气法 (dìng qì fǎ, 'steady term method'). Under this method, the determination of solar terms is similar to the astronomical determination of the special cases of equinox and solstice dates, with different ecliptic longitudes to solve for. One can start with an approximation and then perform a correction using the anomalies and mean motion of the sun. The JPL Horizons On-Line Ephemeris System may be used to query for exact times of solar terms.

The older method is known as 平气法 (píng qì fǎ, 'equal term method') and simply divides the tropical year into 24 equal parts.

Regional note

In Japan, the term Setsubun (節分) originally referred to the eves of Risshun (立春, 315°, the beginning of Spring), Rikka (立夏, 45°, the beginning of Summer), Risshū (立秋, 135°, the beginning of Autumn), and Rittō (立冬, 225°, the beginning of Winter), but currently mostly refers to the day before Risshun. The name of each solar term also refers to the period of time between that day and the next solar term, or 1/24th of a year.

See also


This page was last updated at 2023-10-29 16:48 UTC. Update now. View original page.

All our content comes from Wikipedia and under the Creative Commons Attribution-ShareAlike License.


Top

If mathematical, chemical, physical and other formulas are not displayed correctly on this page, please useFirefox or Safari