Decorative drums of the Drum Tower, Xi’an, Shaanxi province.

The twenty-four drums around the tower represent the twenty-four solar terms (节气 jiéqi) of the Chinese lunisolar calendar. Right now we are in 寒露 (hánlù), the cold dew, the first term after 秋分 (qiūfēn), the autumnal equinox. People in China are sensitive to the slight changes in weather that each term describes.