It's late autumn. When the cool wind comes, the cold dew comes, the reeds fly lightly, and the forests are dyed. In the twinkling of an eye, the autumn was once colder, and we welcomed the cold dew solar term. "The wind is moving slowly and the cold dew is falling." If the White Dew Solar Term marks the transition from hot weather to cool weather, then the Cold Dew is a watershed from cool weather to cold weather. As the Collection of Seventy Two Days of the Month says, "On September Day, the dew will be cold and will condense." In the deep autumn, the dew is heavy, the temperature is lower, and the dew is colder, so it will condense into frost. Everything will disappear with the increase of the cold, and the world will become cool and ethereal. Natural changes give each solar term corresponding phenology. The ancients divided the cold dew into three stages: "The first stage is for the guests from the wild geese, the second stage is for the birds to enter the flood, and the third stage is for the chrysanthemums." In the cold dew season, the wild geese line up in the sky and migrate southward. In late autumn, birds and birds were nowhere to be found. Suddenly, there were many clams on the beach, and chrysanthemums were blooming proudly in the rustling autumn wind. Four seasons of circulation, the scenery is affectionate. When wild geese fly south and chrysanthemums are in full bloom, scholars and writers think in autumn and draw colorful pictures of late autumn. Look, Lu Lun's cold dew is "several schools of clear spring Huang Jusheng, one forest of cold dew and purple pears are flourishing", one school is bright and luxuriant; In Wang Anshi's eyes, "The autumn is long in the empty court, and the cold dew falls into the twilight to worry about the clothes", full of loneliness and melancholy; Yuan Zhen described in his poem that "the cold dew startles the autumn evening, and the chrysanthemums turn yellow in the morning. The wind of thousands of families sweeps the leaves, and the wild geese follow the sun", which is filled with the spirit of death. The writers express their feelings when they feel it, so the Cold Dew Solar Term has a bit more poetic and lasting appeal. For thousands of years, the change of seasons has also influenced and shaped the Chinese people's eating, living and living habits, forming a unique solar term custom culture. Before and after the cold dew, the temperature difference between day and night is large, and the autumn dryness is obvious. According to the health preservation theory of "nourishing yang in spring and summer, nourishing yin in autumn and winter" of traditional Chinese medicine, people should nourish yin to prevent dryness, moisten the lungs and benefit the stomach at this time. Sesame is a good product for strengthening the spleen and stomach, harmonizing the five internal organs, and anti-aging. Therefore, the folk custom of "eating sesame with cold dew" came into being. Cold Dew Tea also has a unique flavor. The tea picked in the first three days and the last four days of the Cold Dew Solar Term every year is called "Zhengqiu Tea", which is a high-quality autumn tea that people pursue. It is neither as fresh and tender as spring tea, nor as dry and bitter as summer tea. It has a sweet and mellow fragrance, which is especially popular with old tea drinkers. In the south of the Yangtze River, people still have the custom of eating crabs and fishing in cold dew. As the temperature drops rapidly, the sun can no longer penetrate the deep water, so the fish will swim to the shallow water area with higher water temperature, so there is a saying of "fishing in autumn". In the cold dew season, autumn is high and cool. It is a good time to travel. Climbing, appreciating chrysanthemums and watching red leaves have become traditional folk activities that have been carried forward to this day. In Beijing, Xiangshan red leaves attract a large number of tourists every year. However, seeing the red leaves all over the mountain and the red leaves at the foot of the mountain, people in the scene feel the tranquility and comfort of "parking and sitting in the maple forest at night, and the frost leaves are redder than the flowers in February". Eating sesame, drinking autumn tea, tasting crabs, and appreciating maple leaves. In the cold dew season, the wisdom of the old ancestors' life is touched between the lips and teeth, and the vast and peaceful landscape of the world and mountains is laid out in front of us. There is a special taste lingering in our minds! The cold dew solar term is also a busy time for farming. A farmer sang: "It's getting colder in the cold dew season