They are open in season and order.

The season is 24 solar terms: beginning of spring, rain, sting, vernal equinox, Qingming and Grain Rain in order in spring; Summer, long summer, small full, busy, summer solstice, small trees, big trees appear in turn. Autumn is followed by beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew and First Frost. Winter is beginning of winter, and light snow, heavy snow, winter solstice, slight cold and severe cold appear in turn. People can remember this song according to the 24 solar terms:

The spring rain shakes the spring and the valley days, and the summer is full of mountains and summers.

Autumn dew, autumn cold and frost, winter snow and winter cold.