Hanlu, Cold Dew, is the seventeenth solar term, at the sun's longitude of 195 degrees, around the eighth of October. It is a sectional (jie) term. Its name marks dew grown cold and near to freezing as the chill of late autumn deepens. In the farming almanac it is the time to bring in the late crops and to sow winter wheat before the frosts, and it is associated with the last warmth of the season, with autumn outings, and with the appreciation of chrysanthemums. 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 twenty-four-fold division of the tropical year into equal solar arcs, each term a fifteen-degree step of the sun.
Hanlu, Cold Dew, falls at 195 degrees, around 8 October, and is a jie, or sectional, term, whose name marks a further step in the cooling sequence begun by Bailu's white dew a month earlier, the dew now cold enough that traditional reckoning treats it as foreshadowing frost rather than the mild condensation of early autumn. In traditional Chinese medicine's seasonal framework, Hanlu is treated as the point at which dietary and lifestyle advice shifts more decisively toward warming foods and protecting the body's yang energy against the advancing cold, part of the broader system of correlating diet and daily conduct with the twenty-four terms that also underlies customs recorded at Dashu and Xiaoshu earlier in the year.