Cooling degree days measure the demand for energy needed to cool a building in a defined region. When temperatures rise above a defined temperature for that region, buildings typically require cooling. A cooling degree day is represented by the number of degrees that the average temperature rises above the defined temperature.
For example, if the average temperature for a day in a region is defined as 85° F and the degree days reference point temperature for that region is 65° F, the cooling degree (day) value for that day is 20. Maintaining this temperature data for regions, helps us understand the relationship between degree days, energy consumption, and the resulting carbon emissions.
See heating degree day day and degree day reference point.