The fear of epidemics inspired physicians, natural philosophers, and government officials to study the effects of weather on health, or, in other words, medical meteorology. These individuals were strongly influenced by prevalent Hippocratic ideas about the link between the environment and the incidence and mortality of different diseases. Medical meteorologists took a passionate interest in recording weather and disease observations often over a period of several years, and most of their accounts included quantitative information.

The motivation for this quantitative approach came in part from the relatively new belief that numbers, the tabular display of numbers, and the comparison of numbers would yield new knowledge about the causes and courses of epidemics and other diseases. Two developments undergirded this trust in numbers. First, the creation of techniques to analyze mortality numerically (initiated by John Graunt and successfully deployed by James Jurin in the inoculation debates) had set a new model for medicine. Second, the invention of instruments to measure temperature, air pressure, and humidity had transformed the study of meteorology. Developed over the course of the seventeenth century by many natural philosophers, including Galileo, Torricelli, Huygens, Hooke, and Wren, these instruments frequently incorporated numerical scales into their design, thus allowing for the quantification of weather phenomena.