DEGREEDAY
Degree day
A degree day is a measure of heating or cooling. Total degree days from an appropriate starting date are used to plan the planting of crops and management of pests and pest control timing. Weekly or monthly degree-day figures may also be used within an energy monitoring and targeting scheme to monitor the heating and cooling costs of climate controlled buildings, while annual figures can be used for estimating future costs.The above text is a snippet from Wikipedia: Degree day
and as such is available under the Creative Commons Attribution/Share-Alike License.