Shuangjiang (Frost Descent)
Shuangjiang is the moment the Sun reaches 210° of apparent ecliptic longitude. It is one of the twelve "Qi", which do not move the BaZi month boundary.
Shuangjiang in 2020–2035
| Year | Instant (UTC+8) | Day |
|---|---|---|
| 2020 | 2020-10-23 06:59:34 | Fri |
| 2021 | 2021-10-23 12:51:10 | Sat |
| 2022 | 2022-10-23 18:35:43 | Sun |
| 2023 | 2023-10-24 00:20:50 | Tue |
| 2024 | 2024-10-23 06:14:47 | Wed |
| 2025 | 2025-10-23 11:50:56 | Thu |
| 2026 | 2026-10-23 17:37:57 | Fri |
| 2027 | 2027-10-23 23:32:52 | Sat |
| 2028 | 2028-10-23 05:13:24 | Mon |
| 2029 | 2029-10-23 11:08:08 | Tue |
| 2030 | 2030-10-23 17:00:35 | Wed |
| 2031 | 2031-10-23 22:49:27 | Thu |
| 2032 | 2032-10-23 04:46:15 | Sat |
| 2033 | 2033-10-23 10:27:37 | Sun |
| 2034 | 2034-10-23 16:16:28 | Mon |
| 2035 | 2035-10-23 22:16:11 | Tue |
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 Shuangjiang about 5 hours 49 minutes later each year until a leap day pulls it back. That is the whole reason Shuangjiang 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