Solar term

A solar term is any of 24 points in traditional East Asian 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 in East Asian calendars; which month is repeated depends on the position of the sun at the time.

Solar terms originated in China, then spread to Korea, Vietnam, and Japan. This is exhibited by the fact that traditional Chinese, Hanja, and Kanji characters for most of the solar terms are identical.

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. Each solar term is divided into three pentads (候 hou), so there are 72 pentads in a year. Each pentad consists of five, rarely six, days, and are mostly named after biological or botanical phenomena corresponding to the pentad.

List of solar terms

Longi- tude	Usual translation	Chinese name ¹	Japanese name	Korean name ²	Constellation	Date ³	Remark
315°	start of spring	立春 lìchūn	立春 risshun	입춘 (立春) ipchun	Capricornus	Feb 4
330°	rain water	雨水 yǔshuǐ	雨水 usui	우수 (雨水) usu	Aquarius	Feb 19	more rain than snow
345°	awakening of insects	驚蟄 (惊蛰) jīngzhé	啓蟄 keichitsu	경칩 (驚蟄) gyeongchip	Aquarius	Mar 6	lit. awakening of hibernating insects. See the note at #Solar term.
0°	vernal equinox	春分 chūnfēn	春分 shunbun	춘분 (春分) chunbun	Pisces	Mar 21	lit. spring division (or center)
15°	clear and bright	清明 qīngmíng	清明 seimei	청명 (清明) cheongmyeong	Pisces	Apr 5	time for tending graves
30°	grain rain	穀雨 (谷雨) gǔyǔ	穀雨 kokuu	곡우 (穀雨) gogu	Aries	Apr 20	lit. Cereal grain rain: rain helps grain grow
45°	start of summer	立夏 lìxià	立夏 rikka	입하 (立夏) ipha	Aries	May 6
60°	grain full	小滿 (小满) xiǎomǎn	小満 shōman	소만 (小滿) soman	Taurus	May 21	grains are plump
75°	grain in ear	芒種 (芒种) mángzhòng	芒種 bōshu	망종 (芒種) mangjong	Taurus	Jun 6	lit. awns (beard of grain) grow
90°	summer solstice	夏至 xiàzhì	夏至 geshi	하지 (夏至) haji	Gemini	Jun 21	lit. summer extreme (of sun's height)
105°	minor heat	小暑 xiǎoshǔ	小暑 shōsho	소서 (小暑) soseo	Gemini	Jul 7
120°	heat	大暑 dàshǔ	大暑 taisho	대서 (大暑) daeseo	Cancer	Jul 23
135°	start of autumn	立秋 lìqiū	立秋 risshū	입추 (立秋) ipchu	Cancer	Aug 8
150°	limit of heat	處暑 (处暑) chǔshǔ	処暑 shosho	처서 (處暑) cheoseo	Leo	Aug 23	lit. dwell in heat
165°	white dew	白露 báilù	白露 hakuro	백로 (白露) baekro	Leo	Sep 8	condensed moisture makes dew white
180°	autumnal equinox	秋分 qiūfēn	秋分 shūbun	추분 (秋分) chubun	Virgo	Sep 23	lit. autumn division (or center)
195°	cold dew	寒露 hánlù	寒露 kanro	한로 (寒露) hanlo	Virgo	Oct 8
210°	frost descent	霜降 shuāngjiàng	霜降 sōkō	상강 (霜降) sanggang	Libra	Oct 23	appearance of frost and descent of temperature
225°	start of winter	立冬 lìdōng	立冬 rittō	입동 (立冬) ipdong	Libra	Nov 7
240°	minor snow	小雪 xiǎoxuě	小雪 shōsetsu	소설 (小雪) soseol	Scorpius	Nov 22
255°	major snow	大雪 dàxuě	大雪 taisetsu	대설 (大雪) daeseol	Ophiuchus	Dec 7
270°	winter solstice	冬至 dōngzhì	冬至 tōji	동지 (冬至) dongji	Sagittarius	Dec 22	lit. winter extreme (of sun's height)
285°	minor cold	小寒 xiǎohán	小寒 shōkan	소한 (小寒) sohan	Sagittarius	Jan 6
300°	major cold	大寒 dàhán	大寒 daikan	대한 (大寒) daehan	Capricornus	Jan 20

1. Simplified Chinese characters are shown in parentheses if they differ from the Traditional Chinese characters.
2. Hanja is indicated in parentheses.
3. Date can vary within a ±1 day range.

The "Song of Solar Terms" (Chinese: 節氣歌; pinyin: jiéqìgē) is used to ease the memorization of jiéqì:

Chinese

春雨驚春清穀天 夏滿芒夏暑相連 秋處露秋寒霜降 冬雪雪冬小大寒 每月兩節不變更 最多相差一兩天 上半年來六、廿一 下半年是八、廿三

Pinyin

chūn yǔ jīng chūn qīng gǔ tiān, xià mǎn máng xià shǔ xiāng lián, qiū chù lù qiū hán shuāng jiàng, dōng xuě xuě dōng xiǎo dà hán. měi yuè liǎng jié bù biàn gēng, zùi duō xiāng chā yī liǎng tiān shàng bàn nián lái liù, niàn yī xià bàn nián shì bā, niàn sān

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

• Chinese calendar
• Korean calendar
• Japanese calendar

External links

• 24 Solar Terms - Hong Kong Observatory
• Chinese calendar with upcoming solar terms in current year
• Chinese Calendar info by David B. Kelley