Guyu (Grain Rain)
Guyu is the moment the Sun reaches 30° of apparent ecliptic longitude. It is one of the twelve "Qi", which do not move the BaZi month boundary.
Guyu in 2020–2035
| Year | Instant (UTC+8) | Day |
|---|---|---|
| 2020 | 2020-04-19 22:45:29 | Sun |
| 2021 | 2021-04-20 04:33:23 | Tue |
| 2022 | 2022-04-20 10:24:18 | Wed |
| 2023 | 2023-04-20 16:13:37 | Thu |
| 2024 | 2024-04-19 21:59:47 | Fri |
| 2025 | 2025-04-20 03:56:01 | Sun |
| 2026 | 2026-04-20 09:39:08 | Mon |
| 2027 | 2027-04-20 15:17:38 | Tue |
| 2028 | 2028-04-19 21:09:31 | Wed |
| 2029 | 2029-04-20 02:55:42 | Fri |
| 2030 | 2030-04-20 08:43:36 | Sat |
| 2031 | 2031-04-20 14:31:14 | Sun |
| 2032 | 2032-04-19 20:14:10 | Mon |
| 2033 | 2033-04-20 02:13:08 | Wed |
| 2034 | 2034-04-20 08:03:44 | Thu |
| 2035 | 2035-04-20 13:48:59 | Fri |
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 Guyu about 5 hours 49 minutes later each year until a leap day pulls it back. That is the whole reason Guyu 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