On the 'best' temperature and precipitation normals: the Illinois situation.

Abstract

Historical (1901-79) temperature and precipitation data for four Illinois stations were used to determine the frequency with which summer and winter averages for periods of various length (ie. different climatic normals) are closest to the value for the next year, and hence its best predictor. The normal achieving the highest frequency in this regard is considered the best for characterizing the recent climate for a given point in time and assessing the abnormality of the following year.-from Authors