Autumn Equinox 秋分 · Qiufen
The Autumn Equinox 2026 falls on 2026-09-23, Wed, at 08:05:14 UTC+8 — the instant the Sun reaches 180° of apparent ecliptic longitude. It is an astronomical moment, not a day: it happens at the same instant everywhere on Earth, and the local date shifts with your time zone.
The same instant is 秋分 (qiufen) in the Chinese solar calendar, where it is one of the twenty-four terms. It is one of the twelve "Qi", which do not move the BaZi month boundary.
The other three cardinal points: Spring Equinox · Summer Solstice · Winter Solstice
Qiufen in 2020–2035
| Year | Instant (UTC+8) | Day |
|---|---|---|
| 2020 | 2020-09-22 21:30:40 | Tue |
| 2021 | 2021-09-23 03:21:05 | Thu |
| 2022 | 2022-09-23 09:03:43 | Fri |
| 2023 | 2023-09-23 14:49:58 | Sat |
| 2024 | 2024-09-22 20:43:42 | Sun |
| 2025 | 2025-09-23 02:19:20 | Tue |
| 2026 | 2026-09-23 08:05:14 | Wed |
| 2027 | 2027-09-23 14:01:43 | Thu |
| 2028 | 2028-09-22 19:45:20 | Fri |
| 2029 | 2029-09-23 01:38:31 | Sun |
| 2030 | 2030-09-23 07:26:55 | Mon |
| 2031 | 2031-09-23 13:15:19 | Tue |
| 2032 | 2032-09-22 19:10:55 | Wed |
| 2033 | 2033-09-23 00:51:41 | Fri |
| 2034 | 2034-09-23 06:39:35 | Sat |
| 2035 | 2035-09-23 12:38:58 | Sun |
Why it is not the same date every year
A tropical year runs about 365.2422 days while a calendar year is a whole 365 or 366. The leftover quarter-day accumulates, pushing Qiufen about 5 hours 49 minutes later each year until a leap day pulls it back. That is the whole reason Qiufen lands on different dates across 2020–2035 and drifts within roughly a day: the term itself is perfectly regular — every 15° of longitude — and the wobble belongs to the calendar, not the sky.
By term
- Chunfen
- Qingming
- Guyu
- Lixia
- Xiaoman
- Mangzhong
- Xiazhi
- Xiaoshu
- Dashu
- Liqiu
- Chushu
- Bailu
- Qiufen
- Hanlu
- Shuangjiang
- Lidong
- Xiaoxue
- Daxue
- Dongzhi
- Xiaohan
- Dahan
- Lichun
- Yushui
- Jingzhe
Sources
- lunar-javascript (6tail, MIT) — solar-term instants, 干支 pillars, 大運/流年, 胎元/命宮/身宮 and the almanac tables.
- Hong Kong Observatory, Date and Time of the 24 Solar Terms — the reference used to check solar-term instants.
- Xieji Bianfang Shu and Sanming Tonghui — classical sources for the Wuhu Dun and Wushu Dun stem rules, hidden stems and the Ten Gods.
Algorithms last checked: 2026-07 · Method and accuracy