Solar term

The solar terms used to mark the midpoint of the month (marked with "Z", for Chinese: 中氣; pinyin: zhōngqì ) are considered the major terms, while the solar terms used to mark the start of the month (marked with "J", for Chinese: 節氣; pinyin: jiéqì ) are deemed minor. The year starts with Lichun (J1) and ends with Dahan (Z12).^[8]

The "Song of Solar Terms" (traditional Chinese: 節氣歌; simplified Chinese: 节气歌; 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.

The modern definition using ecliptic longitudes, introduced by the Shixian calendar, is known as dìngqì fǎ (定氣法; '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.^[18] The JPL Horizons On-Line Ephemeris System may be used to query for exact times of solar terms.

The older method, called the píngqì fǎ (平氣法; 'equal term method'), simply divides the tropical year into 24 equal parts.

• Chinese calendar
• Korean calendar
• Japanese calendar
• Vietnamese calendar
• Wheel of the Year

1. ^ "24 Chinese Feasts (Jiéqì, 节气), equivalent to the 24 Chinese Solar Terms". Chinese calendar. asia-home.com.
2. ^ Until 1644 (Chinese Empire and its tributary states) a period of time of the solar year itself had been equally divided instead of the spatial zodiac.
3. ^ When a lunar month's end does not reach a midpoint of the solar terms, it is regarded as the last month's intercalary one instead of the true "next" month. It is called 歲中閏月法 lit. "midpoint intercalating system".
4. ^ Book of Documents.
5. ^ Ban, Gu. Book of Han.
6. ^ なぜずれる？ 二十四節気と季節感 (Why off-point? -solar terms and our real feeling of the seasons) Maritime Japan, for example, comparing the climate of Taiyuan with that of Tokyo and Kyoto: on Japanese islands differences in seasonal gap lengths are the main problem. In subtropical or tropical regions including southern China climate difference is more serious.
7. ^ "UNESCO – The Twenty-Four Solar Terms, knowledge in China of time and practices developed through observation of the sun's annual motion". ich.unesco.org. Retrieved 9 March 2021.
8. ^ Aslaksen, Helmer. "When is Chinese New Year?" (PDF). Archived from the original (PDF) on 13 March 2009. Retrieved 27 July 2019.
9. ^ Simplified Chinese characters are shown in parentheses if they differ from the Traditional Chinese characters.
10. ^ Hangul are shown in parentheses. For Hangul and romanisation, where the pronunciation differs between South Korea and North Korea, the South Korean pronunciation is given first before the slash, followed by the North Korean pronunciation.
11. ^ "The 24 Solar Terms". Hong Kong Observatory.
12. ^ 二十四节气上了北京冬奥开幕式，牛！ [The 24 solar terms were used in the opening ceremony of the Beijing 2022 Winter Olympics. Awesome!]. China News (in Chinese).
13. ^ Date can vary within a ±1 day range.
14. ^ the Yushui and Jingzhe have been exchanged by Liu Xin in Han dynasty.
15. ^ the Jingzhe and Yushui have been exchanged by Liu Xin in Han dynasty.
16. ^ the Qingming and Guyu have been exchanged by Liu Xin in Han dynasty.
17. ^ the Guyu and Qingming have been exchanged by Liu Xin in Han dynasty.
18. ^ "Determination of Equinox and Solstice Dates". farside.ph.utexas.edu.

• 24 Solar Terms calculator
• 24 Solar Terms – Hong Kong Observatory
• Twenty Four Solar Terms and Their Customs in China
• Chinese calendar with upcoming solar terms in current year
• 24 Sekki – NAOJ > ECO > Glossary >
• Twenty-four Solar Terms and meaning
• Date and time of Solar Terms
• The 24 Solar Terms