Definition of "degree day" []

• A measure of heating or cooling, computed as the integral of a function of time that generally varies with temperature. (noun)
• A unit used in estimating the fuel consumption for a building; equal to the number of degrees that the mean temperature, for a 24-hour day, is below the base temperature, often 65F. (noun)

Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License