Dahan (Major Cold)
Dahan is the moment the Sun reaches 300° of apparent ecliptic longitude. It is one of the twelve "Qi", which do not move the BaZi month boundary.
Dahan in 2020–2035
| Year | Instant (UTC+8) | Day |
|---|---|---|
| 2020 | 2020-01-20 22:54:40 | Mon |
| 2021 | 2021-01-20 04:39:51 | Wed |
| 2022 | 2022-01-20 10:39:06 | Thu |
| 2023 | 2023-01-20 16:29:32 | Fri |
| 2024 | 2024-01-20 22:07:22 | Sat |
| 2025 | 2025-01-20 04:00:08 | Mon |
| 2026 | 2026-01-20 09:44:56 | Tue |
| 2027 | 2027-01-20 15:29:50 | Wed |
| 2028 | 2028-01-20 21:21:57 | Thu |
| 2029 | 2029-01-20 03:00:53 | Sat |
| 2030 | 2030-01-20 08:54:24 | Sun |
| 2031 | 2031-01-20 14:47:58 | Mon |
| 2032 | 2032-01-20 20:31:19 | Tue |
| 2033 | 2033-01-20 02:32:48 | Thu |
| 2034 | 2034-01-20 08:27:19 | Fri |
| 2035 | 2035-01-20 14:14:16 | Sat |
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 Dahan about 5 hours 49 minutes later each year until a leap day pulls it back. That is the whole reason Dahan 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