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Winter Solstice 冬至 · Dongzhi

The Winter Solstice 2026 falls on 2026-12-22, Tue, at 04:50:14 UTC+8 — the instant the Sun reaches 270° 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 冬至 (dongzhi) 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 · Autumn Equinox

Dongzhi in 2020–2035

YearInstant (UTC+8) Day
2020 2020-12-21 18:02:21 Mon
2021 2021-12-21 23:59:19 Tue
2022 2022-12-22 05:48:12 Thu
2023 2023-12-22 11:27:20 Fri
2024 2024-12-21 17:20:35 Sat
2025 2025-12-21 23:03:05 Sun
2026 2026-12-22 04:50:14 Tue
2027 2027-12-22 10:42:10 Wed
2028 2028-12-21 16:19:41 Thu
2029 2029-12-21 22:14:08 Fri
2030 2030-12-22 04:09:37 Sun
2031 2031-12-22 09:55:33 Mon
2032 2032-12-21 15:55:57 Tue
2033 2033-12-21 21:46:01 Wed
2034 2034-12-22 03:34:01 Fri
2035 2035-12-22 09:30:53 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 Dongzhi about 5 hours 49 minutes later each year until a leap day pulls it back. That is the whole reason Dongzhi 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

Sources

  1. lunar-javascript (6tail, MIT) — solar-term instants, 干支 pillars, 大運/流年, 胎元/命宮/身宮 and the almanac tables.
  2. Hong Kong Observatory, Date and Time of the 24 Solar Terms — the reference used to check solar-term instants.
  3. 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