This essay studies painted dragons, zoomorphic tools of human intervention in the water cycle without correlative in empirical science. By demonstrating the relation of pictorial form to meteorological phenomena in dragon paintings used to summon rain, by arguing that the process of painting dragons mimicked, and thus effected, atmospheric events, and by suggesting how artistic repetition and repeated spectatorship of efficacious dragon paintings produced predictable meteorological outcomes, this essay shows how iconology and ecology converged in dragon painting during the Song and Yuan dynasties. This essay reveals that artistic and meteorological correspondences of form, process, and repetition aligned representational and climatological concerns, the shared language of art-historical description and ritual prescription establishing the painter as rainmaker and the rainmaker as painter. Ultimately, this essay suggests that control over the production, reproduction, and viewing of dragon images constituted the power to produce atmospheric events on demand.