Heating Degree Day (HDD)

Difference between the actual temperature, as determined by the average of the high and low daily temperatures, and 65 degrees F. For example, if the daily high temperature is 55 degrees and the daily low is 35 degrees, the actual temperature for that day would be 45 degrees. The HDD’s for that day would be 20 (65-45). If the average temperature is greater than or equal to 65 degrees, the HDD’s for the day would be zero