Revisiting the Thornthwaite and Mather Water Balance1

This technical note clarifies confusion currently present in research using and/or citing the 1955 and 1957 editions of the Thornthwaite and Mather Water Balance (or Budget) resulting from corrections to errant tables in the 1955 edition made by the authors for the 1957 edition. Confusion over the two editions and the formulas used have clouded the results of research, management, and educational publications ever since, resulting in frequent misunderstanding of the method's utility as well as how its results compare with other frequently used methods for estimating evapotranspiration.