Minor Heat小暑

Minor Heat (小暑, Xiǎo Shǔ) is the eleventh of the twenty-four solar terms and the month-opener that follows the Summer Solstice. It is an astronomical instant, not a day: the moment the sun reaches 105° of ecliptic longitude, which falls somewhere between 6 and 8 July depending on the year.

The name is comparative rather than absolute — 小 means "lesser", set against Major Heat two weeks later. It does not mean the heat is mild; it means the heat that follows is worse. Minor Heat opens the stretch of the year the name family describes as building toward its peak, not the peak itself.

It sits between the Summer Solstice and Major Heat, roughly two weeks out from each, in the run of the year when daytime temperatures are climbing fastest even as daylight itself has already begun shortening. In the agricultural calendar it names the start of the hot, humid stretch that many summer crops depend on and that many summer storms arrive in.

Minor Heat is a 節 — a month-opening term — so at the instant the sun crosses 105° the month pillar's branch becomes 未 (Wèi). This is the term that puts 未 in place for anyone born from this instant forward until the next 節, Beginning of Autumn, arrives roughly a month later.

This site's calculator applies that rule at the astronomical instant, not on a fixed calendar date: a birth in the days around 6–8 July can carry either 午 (from Grain in Ear, the previous 節) or 未, depending on which side of the crossing the birth time falls.

Major Heat (大暑) and End of Heat (處暑) — The twenty-four solar terms. All three English names carry the word "heat", but only Minor Heat is a 節. Major Heat and End of Heat are both 氣 and change no pillar; Minor Heat is the one that opens the 未 month pillar on its own.