The six solar terms of autumn

Traditional autumn

Autumn's six solar terms follow a gradual change from lingering summer heat to dew, cooling nights and frost. Harvest, migrating birds and retreating insects give the season another thread: gathering what has grown and preparing for winter. The sequence begins with Liqiu in early August and ends with Shuangjiang, which continues until Lidong opens winter in early November.

The September equinox lies in the middle of traditional autumn. Liqiu begins at solar longitude 135°, halfway in angular position between the June solstice at 90° and the September equinox at 180°. Solar longitude measures the Sun's position along its apparent annual path across the sky.

The six autumn terms

Each row gives the beginning of a term in 2026. A term lasts until the next one begins, roughly fifteen days later.

Beginning of Autumn (Liqiu)

The li in Liqiu marks a beginning. Its traditional images are cool winds, white dew and singing autumn cicadas: signs of the season's first changes. These belong to the seventy-two pentads, which assign three successive seasonal markers to each solar term.

Liqiu can arrive while summer heat remains strong across much of China. The following term, End of Heat, distinguishes the later easing of warmth from this formal beginning of autumn.

End of Heat (Chushu)

The chu in Chushu is traditionally explained as stopping or coming to an end. The name describes the waning of summer heat as August advances.

Ripening grain is one of its traditional markers. Alongside the retreat of heat, the term turns attention to bringing in the harvest.

White Dew (Bailu)

Bailu evokes the gleam of dew on grass and leaves after a cool night. Dew forms when a surface cools to the dew point, the temperature at which water vapour begins to condense into liquid droplets. Clear skies, light winds and adequate moisture favour its formation; longer autumn nights allow more time for cooling.

The name also carries a symbolic meaning: traditional Chinese seasonal associations link autumn with metal and the colour white. Bailu's three seasonal markers bring birds into the picture: wild geese arrive, swallows depart and birds store food for winter. Dew on the ground and changes in bird activity become parallel signs of autumn.

Autumn Equinox (Qiufen)

Qiufen is the September equinox, when the Sun crosses the celestial equator southward. The celestial equator is the projection of Earth's equator onto the sky. The name means the division of autumn, placing the equinox in the middle of the traditional season. Northern Hemisphere days continue to shorten as the Sun moves farther south.

Day and night are close to equal. Sunrise and sunset are measured using the Sun's upper edge, and the atmosphere bends its light, allowing it to remain visible when it is geometrically below the horizon. These effects make the daylight interval a little longer than twelve hours.

Mid-Autumn Festival follows a different calendar rule: lunar month 8, day 15. It shares the season with Qiufen, but the equinox does not determine the festival's date.

Cold Dew (Hanlu)

Hanlu, Cold Dew, deepens the cooling imagery introduced by Bailu. Its name evokes dew on increasingly cold mornings, taking the season from early autumn's freshness towards a sharper chill. The dew is still liquid water; the name emphasizes the colder conditions around it.

Later-arriving flocks of wild geese and yellow chrysanthemums belong to its traditional markers. The geese extend the migration imagery of Bailu, while the flowers give the cooling landscape a late display of colour.

Frost's Descent (Shuangjiang)

Shuangjiang brings the autumn sequence to its final stage. Its name looks towards frosty mornings, while its traditional markers include yellowing and falling leaves and insects withdrawing into dormancy.

Despite the word “descent,” hoar frost grows on a sufficiently cold surface as water vapour turns directly into ice crystals. Its formation depends on both surface temperature and the available moisture. An exposed leaf or blade of grass can cool below 0°C even while air measured above the ground remains above freezing. This is a further stage of cooling beyond the liquid dew evoked by Bailu and Hanlu.

Autumn in different landscapes

The seasonal imagery has its roots in the Yellow River basin. A colder northern or upland landscape may see frost well before Shuangjiang, while a warm southern one may see none during the term. Harvests likewise depend on the crops being grown. The six terms provide a shared sequence through autumn without making every landscape follow the same timetable.