Heating Degree Days are a measure of the coldness of the weather experienced, based on the extent to which the daily mean temperature falls below a reference temperature (65° F). For example, on a day when the mean outdoor dry-bulb temperature is 35°F, there would be 30 degree-days experienced. (A daily mean temperature represents the sum of the high and the low readings divided by two.)

The AGA Heating Degree Day Report contains heating degree data aggregated on a weekly and monthly basis for the current year and prior year.  Also included are weather normals for each of the nine Census Regions and the U.S.

Historic Heating Degree Day Data

Weekly Regional Heating Degree Day