The Chinese special Twenty-Four Solar Terms
The sun starts from the vernal equinox point(at this point，the sun’s rays are perpendicular with the equator，and advances 15 degrees during one solar term，circulating one cycle and returning back to the vernal equinox point．Today in our Chinese learning online lesson, this is called one tropical year，adding up to 360 degrees，exactly24 solar terms．
The twenty-four solar term calendar and the Gregorian calendar dates are approximately the same year, the first half of the year occurs around the date of 6 or 21 of every month (summer solstice), and the next half on about 8 and 23．By learning Chinese ancient schedules, the agricultural calendar，you can realize that solar term dates are difficult to ascertain. As the beginning of spring，for example，could begin one year as early as December 15，and the latest date could be January 15．
From the name twenty-four solar terms in our online Chinese lessons，one can speculate the division in the solar terms gives sufficient consideration to the seasons，climate，seasonal vegetation，and other changes of natural phenomena．The beginnings of spring，summer，autumn，and winter，as well as the vernal and autumnal equinoxes and the summer and winter solstices reflect the seasons’ change．These are determined by divisions on the ecliptic，astronomical angles，the reflecting and turning point of the sun’s altitude variation；differentiating the four seasons．with astronomical angles，the first four are the starts of seasons，and the later four are the turning points of the sun’s altitude variation．Due to China occupying vast regions，possessing extremely distinct monsoon characteristics, and having various continental factors，those result in great differences in the climate．Consequently，the various regions’ four seasons are different. Minor heat，great heat，limit of heat，minor cold，and major cold are five solar terms reflecting degrees of temperature．Rain，grain rain，minor snow, and major snow are four solar terms indicating rain and snow precipitation, the time periods，and the severity．cold dew, white dew, and descending frost are the three solar terms regarding water vapor condensation and appearance Yet this essentially reflects the process gradual temperature decline when the air temperature drops to a certain degree，water vapor emerges and forms dew.
As the temperature continues to decline，the condensation increases as it gets colder and colder．When the temperature drops below zero degrees Celsius，water vapor turns to frost full grain and grain in the husk are two solar terms indicating the maturing of domestic crops and harvest time. The terms wakening of insects and clear and bright reflect the occurrence of natural phenomena．In particular，the awakening of insects indicates the first thunderstorm from the heavens stirring. The underground insects from hibernation，indicating the return of spring. That is all for today’s Chinese online lesson as to how to understand Chinese 24 solar terms.