The Chinese Calendar System

A lunisolar calendar explained for English speakers

The Chinese calendar is a lunisolar calendar — it tracks both the phases of the Moon and the position of the Sun. Months follow the lunar cycle (new moon to new moon), while the year stays aligned with the solar seasons through the insertion of a leap month roughly every three years.

Each year is named from a combination of one of 12 zodiac animals (生肖, shēngxiào) and one of 5 elements (五行, wǔ xíng). Because the element advances every two years (one yang 陽 year followed by one yin 陰 year), the full cycle of unique animal-element pairings repeats every 60 years — the jiǎzǐ (甲子) cycle.

How the months work

A Chinese month follows the natural observable lunar cycle. A normal year has 12 such months (about 354 days), which is roughly 11 days shorter than the solar year of 365 days.

To aligned the chinese lunar calendar with the seasons, a leap month is inserted every 32-33 months — seven leap months over nineteen years. This is the Metonic Cycle which the Hebrew calendar also uses.

The 24 solar terms

The solar calendar is divided into 24 solar terms (節氣, jiéqì), each of approximately 15 days.

The winter solstice (冬至, dōngzhì, ~22 Dec) and the spring equinox (春分, chūnfēn, ~20 Mar) are two of the twelve major solar terms that anchor the system. The first lunar month (正月) is defined as the month that contains the major term 雨水 (yǔshuǐ, "rain water", ~19 Feb), and Chinese New Year is the first day of that month — the new moon day. This is why it drifts between 21 January and 20 February on the Gregorian calendar.

The 60-year cycle (Jiǎzǐ)

The 12 animals cycle annually: Rat (鼠), Ox (牛), Tiger (虎), Hare (兔), Dragon (龍), Snake (蛇), Horse (馬), Sheep (羊), Monkey (猴), Rooster (雞), Dog (狗), Pig (豬). The 5 elements cycle every two years: Metal (金), Water (水), Wood (木), Fire (火), Earth (土). Together they produce 60 unique year names before the pattern repeats. If you were born in 2024, you were born in the Year of the Wood Dragon — and the next Wood Dragon will not come until 2084.