The North Carolina State Climate Office has added a nifty new tool to their website–a growing degree day calculator that you can use to calculate GDDs for any location in the Southeast, not just North Carolina. The calculator can be found at You start by entering your location, picking a way to calculate GDD, and then picking average periods or years to compare this year to. The output comes in the form of a graph. If you use it inside NC, you will get access to weather from their network, but if you use it in Georgia, for example, you will get data based on National Weather Service stations and interpolated to a grip by PRISM. The website has more details about what databases are used.