Jieqi (or solar terms) are days marking one of the 24 time zones of the solar year in traditional Chinese calendar. Jieqi was used to indicate the alternation of seasons and climate changes in ancient China. It is a unique component and creative invention of Chinese traditional calendar.
Originated in the Yellow River reaches, Jieqi reflected our ancestors, knowledge about climate changes during their farming activities. Over the years, Jieqi has played an important role in China,s agricultural and animal husbandry production. In reality, the actual solstice/equinox dates vary by plus or minus one day, hence the variation between such reference lists as Cohen Introduction 412 and the back of the Mathews dictionary (used here). Readers located in the North Temperate Zone should find the defining events generally familiar; the list was apparently devised for approximately 35, N latitude.
The 24 solar divisions begin with the "Start of Spring", which is followed in turn by "Rain Water", when preparations for planting are made; "Excited Insects", a time of spring thunder and the stirring of new life; the Spring Equinox; "Clear and Bright", marked by the howling of southeasterly winds; and "Grain Rains", reminding the farmers that the seasonal downpours are beginning. The summer divisions begin with "Start of Summer"; "Grain Fills", when the grain swells on the stalks; "Grain in Ear", marking the time of harvest; the Summer Solstice; and "Slight Heat" and "Great Heat", when the warmth of summer becomes increasingly more oppressive.
The summer divisions are followed in turn by the "Start of Autumn", the day on which the temperature begins to cool; "White Dew", when the moisture congeals to frost; the Autumnal Equinox, the true start of the fall season; and followed with "Cold Dew" and " Frost Descends", the weather turns cold as winter nears. The "Start of Winter" is followed by "Light Snow" and "Heavy Snow", which mark the beginning of deep winter. The next division in the year, Winter Solstice, is a day of deep significance, celebrated in Taiwan by eating a kind of sweet dumpling soup called Tangyuan to fortify the body in preparation for the biting frost of "Little Cold" and "Severe Cold", the final two divisions of the cycle before beginning the new year.
-- The Twenty-four Solar Terms
1st solar term: the Beginning of Spring
2nd solar term: Rain Water
3rd solar term: the Waking of Insects
4th solar term: the Spring Equinox
5th solar term: Pure Brightness
6th solar term: Grain Rain
7th solar term: the Beginning of Summer
8th solar term: Grain Full
9th solar term: Grain in Ear
10th solar term: the Summer Solstice
11th solar term: Slight Heat
12th solar term: Great Heat
13th solar term: the Beginning of Autumn
14th solar term: the Limit of Heat
15th solar term: White Dew
16th solar term: the Autumnal Equinox
17th solar term: Cold Dew
18th solar term: Frost,s descent
19th solar term: the Beginning of Winter
20th solar term: Slight Snow
21st solar term: Great Snow
22nd solar term: the Winter Solstice
23rd solar term: Slight Cold
24th solar term: Great Cold