Yuyang Qihou Qinji (《雨旸气候亲机》) is a highly practical manual of weather prediction belonging to the Daoist Thunder Rites (leifa 雷法) tradition of the Song dynasty and preserved in the Ming Zhengtong Daoist Canon (《正统道藏》). The text comprises poems and prose passages, diagrams of clouds, prognostic formulas, and miscellaneous notes, and was intended primarily to assist Daoist practitioners of Thunder Rites in determining the appropriate timing for the performance of their rituals.At its core, the work interweaves experiential techniques such as observing clouds and discerning winds with a tradition of prognostication centered on the asterisms of the Northern Dipper. Folk sayings recorded in the text—for example, “after prolonged rain, a west wind brings clearing weather”—together with its thirty-nine figurative cloud diagrams and prognostic statements such as “when white clouds obscure the Dipper, a major change will occur the following day,” reveal a distinctive epistemological framework. Empirical meteorological knowledge provided evidence for immediate and localized atmospheric conditions, while astral prognostication supplied an explanation in terms of the more fundamental workings of cosmic qi and its transformations. The two were mutually reinforcing within the cosmological framework of the resonance between Heaven and humanity (tianren ganying 天人感应).For its historical users, therefore, this was not a hybrid assemblage of “superstition” and “science,” but an integrated body of knowledge regarded as effective for predicting wind and rain, regulating one’s physical and mental disposition, and orienting human action within the changing patterns of the cosmos.
