Lìxià

Lixia, the Start of Summer, is the seventh solar term, at the sun's longitude of 45 degrees, around the sixth of May. It is a sectional (jie) term and marks the astronomical beginning of summer, when warmth becomes settled and crops enter a phase of rapid growth. In the farming almanac it is a time to tend the fast-growing fields and to guard against early pests and drought. Old customs include the weighing of people to track health through the hot months and the eating of particular seasonal foods to mark the day. Being a solar marker that follows the sun, it falls near the same Gregorian date each year. These are the observances of the East Asian agricultural tradition, resting on the division of the tropical year into twenty-four solar terms of fifteen degrees each.

Lixia, the Start of Summer, falls at 45 degrees, around 5 or 6 May, and is a jie, or sectional, term, opening the second of the traditional calendar's four seasons in the twenty-four-term system. As with Lichun's start of spring, Lixia's astronomical date does not correspond to when temperatures in most of China actually begin to feel like summer, since the solar terms divide the year by the sun's position rather than by observed climate, and the term functioned historically chiefly as an agricultural marker, signalling that rice transplanting and other summer-crop work should be underway. Traditional custom in some regions includes weighing children on this day, a practice associated with wishes for their health through the coming hot season.

The twenty-four solar terms divide the ecliptic into equal arcs of fifteen degrees, and this one falls at 45 degrees of the sun's apparent longitude. It is a sectional term, a jie, one of the twelve that fall in the odd positions of the twenty-four and open the twelve solar months. The sectional terms and the major terms alternate strictly around the year, so a jie is always followed by a zhong fifteen degrees later.

The twelve major terms are what make the Chinese calendar work as a lunisolar one. Each ordinary lunar month is expected to contain exactly one major term, and the month takes its number from the term it contains, so the eleventh month is by definition the one holding the winter solstice. When a lunar month falls entirely between two major terms and contains none, it is declared intercalary and repeats the number of the month before it, which is how a thirteenth month is inserted without any fixed rule about when.

Lixia is the start of summer and one of the four terms that open the seasons, with Lichun, Liqiu and Lidong. Those four fall at the midpoints between the equinoxes and solstices, at 45, 135, 225 and 315 degrees, so the Chinese seasons are centred on the solstices and equinoxes rather than beginning at them, which is a different convention from the astronomical seasons used in Europe and a frequent source of confusion in translation.