Qingming occurs at celestial longitude 15°, around April 4-6. Among the 24 solar terms it is unique in being also one of China's most important traditional festivals (清明節 — Tomb-Sweeping Day).
Tradition: families visit ancestral graves to clean them, offer food and flowers, and burn paper money. Spring outings (踏青) are also traditional. Climate: clear skies, blooming flowers, ideal for outdoor activities.
Qingming's double identity, a calendar node that is also a day off work, is the residue of three older observances merging. Hanshi, the cold-food day on which cooking fires were extinguished, fell a day or two before it. Shangsi, kept by the water for purification and spring excursions, fell close by as well. Over the Tang and Song the Hanshi holiday ran into Qingming, the outing customs of Shangsi drifted across, and Qingming eventually absorbed both — which is why grave-tending and a day out in the countryside now happen on the same date.
The festival is often remembered as falling on 5 April. In fact its date follows the solar term and moves between 4 and 6 April, landing on the 4th fairly often around leap years. What that implies is more interesting: Qingming is one of the very few traditional Chinese festivals dated by the sun, not by the moon. Dragon Boat, Mid-Autumn and Lunar New Year all follow lunar dates and swing widely against the Gregorian calendar, while Qingming barely moves at all. How long the grave-tending season lasts has never been standardised. Some families keep strictly to the day itself; others observe a window of three days before and four after, or seven before and eight after; some treat the whole third lunar month as open. In parts of Fujian and Guangdong certain lineages tend their graves on entirely different dates. The variation follows lineage custom and the demands of the farming calendar, and no nationwide rule has ever existed to settle it.
Classical glosses on the name work from the sense of air that is clear and a world that looks washed and bright, matching how the season appears. Its three pentads are the flowering of the paulownia, field mice giving way to small quail-like birds (phrased with the same changes-into convention used throughout the pentad lists), and the first rainbow of the year. As with other terms, the sequence steps from plants to animals to phenomena in the sky.
For chart work, Qingming is a major term: the Rabbit month ends, the Dragon month (辰 chén) begins, and the month pillar turns. The Dragon branch is far more mixed than the Rabbit, holding earth, wood and water together, and it is classically treated as a reservoir of water. Wood is past its peak and lingers as residual strength while earth rises; damp earth of this kind is read as able to produce metal and to dull fire. Readings of births after Qingming tend to work from that pivot rather than from the single-element clarity of the Rabbit month. Read Chunfen, Qingming and Guyu as a set and the pattern repeats: Chunfen is the mid-term of the Rabbit month, Qingming opens the Dragon month, and Guyu is the Dragon month's mid-term. Qingming is therefore the only point in this stretch at which a pillar changes, and it opens the final month of spring. The thirty days from Qingming to Lixia are treated as the handover from spring wood to summer fire, with the earth element gradually taking charge in between.
Because its date is set by the solar term, not by a fixed calendar day. Qingming begins when the sun reaches 15° of ecliptic longitude, which puts it on 4, 5 or 6 April depending on the year, with the 4th appearing fairly often near leap years. Unlike Dragon Boat or Mid-Autumn, which follow lunar dates, Qingming tracks the sun, so it actually varies less against the Gregorian calendar than most traditional festivals.
They began as separate observances. Hanshi, the cold-food day, fell a day or two earlier and forbade the lighting of cooking fires; Shangsi was a riverside purification and spring-outing day nearby in the calendar. From the Tang and Song onward the holidays ran together and their customs mixed, with Qingming gradually absorbing both. The modern combination of tomb-sweeping and countryside excursions on a single day is the product of that merger.
Yes. Qingming is one of the twelve major terms, so the Rabbit month ends and the Dragon month begins at the moment of transition, taking the Bazi month pillar with it. The Dragon branch conceals earth, wood and water, a very different mixture from the Rabbit's single wood. A birth close to Qingming should be cast against the exact transition time, since the two sides of it belong to different month commands.
There has never been a single rule. Some households go on the day; others observe a window of three days before and four after, or seven before and eight after; some treat the whole third lunar month as available. A number of lineages in Fujian and Guangdong keep entirely different dates. The variation reflects family custom and the farming calendar, not a correct-versus-incorrect distinction.