The only one of the 24 solar terms that is both a solar term and a festival is

Among the 24 solar terms, the only festival that is both a season and a traditional festival is Tomb-Sweeping Day.

Twenty-four solar terms include beginning of spring, rainy day, fright, vernal equinox, Qingming Festival, Grain Rain, Long Summer, Xiaoman, Mangzhong, Summer Solstice, Slight Summer, beginning of autumn, Chushu, Bailu, Vernal Equinox, Cold Dew, First Frost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold.

Among the 24 solar terms, Tomb-Sweeping Day and Tomb-Sweeping Day are both solar terms and traditional festivals, which are also called outing festival, outing festival, March festival and ancestor worship festival. The festival is at the turn of mid-spring and late spring. Tomb-Sweeping Day originated from the ancestral belief and the custom of worshipping spring in ancient times, which has both natural and humanistic connotations. It is both a natural solar term and a traditional festival. Grave-sweeping and outing are the two major themes of Tomb-Sweeping Day etiquette and customs, and these two traditional themes have been passed down from ancient times to the present in China.

The characteristics of the twenty-four solar terms:

Twenty-four solar terms are special festivals in the elephant trunk calendar that express the change of natural rhythm and establish December. At first, it was based on the changing stars. The Big Dipper rotates in a cycle, and bucket handle rotates around the east, south, west and north, which is called one year old. Each rotation cycle begins in beginning of spring and ends in severe cold.

The current twenty-four solar terms are formulated according to the position of the sun on the ecliptic, that is, the sun's trajectory in one year is divided into 24 equal parts, each 15 is 1 equal part, and each 1 equal part is a solar term, starting from beginning of spring and ending from the great cold. Twenty-four solar terms are an important part of the long history and culture of the Chinese nation, which embodies the historical and cultural essence of Chinese civilization.

Twenty-four solar terms are the product of ancient farming civilization, and farming production is closely related to the rhythm of nature. It is a knowledge system formed by ancient ancestors by observing the movement of celestial bodies and understanding the changing laws of time (season), climate and phenology in a year. Each solar term represents different changes in time, climate and phenology.

The twenty-four solar terms express the unique concept of time between human beings and the natural universe, and contain the long-standing cultural connotation and historical accumulation of the Chinese nation. It not only plays a guiding role in agricultural production, but also affects the food, clothing, housing and transportation of ancient people, and even cultural concepts.