Dahan, Major Cold, is the twenty-fourth and final solar term, at the sun's longitude of 300 degrees, around the twentieth of January. It is a principal (zhongqi) term and traditionally the coldest point of the year, the extreme of winter. After it the cycle returns to Lichun and the start of spring, closing the round of twenty-four terms. In the farming almanac it is a time of final preparation for the new year and the coming season, often coinciding with the busy run-up to the Lunar New Year, with the making of festival foods and the setting of the household in order. Being a solar marker, it falls near the same Gregorian date each year. These are the observances of the East Asian agricultural tradition, resting on the astronomical division of the tropical year into twenty-four equal solar arcs.
Dahan, Major Cold, falls at 300 degrees of ecliptic longitude, around 20 January, and is a qi, or major, term, traditionally the last and, in principle, coldest of the twenty-four terms before the cycle closes and returns to Lichun, the Start of Spring, fifteen degrees and roughly two weeks later. Dahan falls close to the Chinese Lunar New Year in most years, since the lunisolar calendar's intercalation keeps the new year anchored to the second new moon after Dongzhi, the winter solstice, and the term is traditionally treated as the period for final preparations, cleaning the home, preparing festival foods and settling debts, before the year's most important festival begins.