Degree days are measures of how cold or warm a location is. ... Heating degree days (HDD) are a measure of how cold the temperature was on a given day or during a period of days. For example, a day with a mean temperature of 40°F has 25 HDD. Two such cold days in a row have a total of 50 HDD for the two-day period.

What are heating and cooling days?

Heating and cooling degree days (HDD and CDD) essentially indicate how hot (or cold) it is outside for a given day and for how long it was at that temperature. This can be more helpful than knowing the temperature alone for estimating how much energy you used on heating and air conditioning.

What are degree days on electric bill?

Degree days are based on how much the average daily outdoor temperature varies from the standard temperature of 65 degrees. So, the colder or hotter the weather, the more degree days there will be. In general, energy bills increase or decrease fairly close to the same percentage that degree days increase or decrease.