A Study of the Severity of the Midwestern Winters of 1977 and 1978 Using Heating Degree Days Determined from Both Measured and Wind Chill Temperatures

Abstract

The winters of 1976?77 and 1977?78 were severe by virtually any standard. In this study, heating degree day (NDD) accumulations for these two winters as well as for the 1941?70 normals are examined at 31 National Weather Service stations in Indiana, Wisconsin, Michigan, Illinois, Ohio, and Kentucky. In addition, a modified heating degree day (MHDD) based on wind chill temperature is accumulated. In both cases, the winter is defined as consisting of the months of December, January, and February. Three-month and one-month accumulations are plotted and analyzed to gain a view of spatial and temporal distributions of both HDD and MUDD. Both parameters are shown to be influenced markedly by the presence of the Great Lakes, an influence that diminishes as an extensive ice cover forms on the lakes. The winter of 1976?77 is found to have greater accumulations of both HDD and MI4DD. A comparative ratio also is calculated in order to give an impression of the extent to which the wind's influence is felt. The ratio values show that for 1976?77 the inclusion of wind data gives the impression of a more intense winter than would be given by temperature data alone. However, the reverse is true for 1977?78; the inclusion of wind data gives the impression of a less intense winter.