In this article, Spanish narrative material and mission harvest data are evaluated as source materials for historic drought analysis, then a more objective drought chronology drawn from southern California tree rings is offered. After presentation of these data, the paper concludes with a discussion of research themes in mission human ecology linked with drought. The article begins with a brief review of drought definitions, attributes of precipitation variability in the historic mission lands, then moves into a discussion of how this variability might be expressed in the Franciscan narratives.