This graph represents the function that gives the average percentage of all-water clouds as a function of cloud temperature, and is based on observational data*. For example, at cloud temperatures of -5 degrees C, 55% of clouds are made up of all-liquid hydrometeors. At cloud temperatures of -10 degrees C, about one-third of all clouds are all-liquid in makeup.

* - Peppler (1940) and Borovikov et al. (1963)