Clicking on the Create Table button will generate a tabular summary of heating and cooling degree day totals, plus corresponding departures from normal, for all available National Weather Service observing stations in Minnesota and adjacent counties in neighboring states. The table also includes divisional and statewide area averages.
Heating and Cooling Degree Day calculations are based on the assumption that when the outside temperature is 65 degrees F (Base 65), heating or cooling a building is not required to maintain human comfort. Daily degree days are the difference between the daily temperature average (high temperature plus low temperature - divided by two) and 65 degrees. If the daily temperature mean is below 65 degrees, the mean is subtracted from 65 degrees and the result is the daily number of Heating Degree Days. If the mean temperature is above 65 degrees, 65 is subtracted from the mean and the result is the daily number of Cooling Degree Days.
For some applications, 50 degrees F (Base 50) is used as a threshold for calculating energy demand for heating buildings.
Adding together daily totals over the course of weeks, months, or a season presents the user with a quantitative measure of cumulative energy demand for the period of interest.