Solar-term entry and the month pillar

The month branch changes at twelve solar-term entry instants, not on calendar day one.

Twelve entries, twelve branches. The twelve large ticks are Jie entries that open month branches; small ticks are mid-terms, not month-branch boundaries. Lichun turns Chou into Yin. — The twelve large ticks are Jie entries that open month branches; small ticks are mid-terms, not month-branch boundaries. Lichun turns Chou into Yin.

This diagram shows only the fixed order of month branches. Entry dates and times vary by year, and the month stem depends on the year stem. An actual birth chart compares the birth instant with the entry instant.

Twelve entries and their month branches

Start of Spring→ Yin month
Awakening of Insects→ Mao month
Clear and Bright→ Chen month
Start of Summer→ Si month
Grain in Ear→ Wu month
Minor Heat→ Wei month
Start of Autumn→ Shen month
White Dew→ You month
Cold Dew→ Xu month
Start of Winter→ Hai month
Major Snow→ Zi month
Minor Cold→ Chou month

Explore all 24 solar terms

Source: MYEONG Saju engine's month-pillar entry rule and twelve Jie order. This is not a chart for a particular year or person.