Heating Degree Days
A heating degree day is defined as: 65°F  mean daily temp QUESTION FOR THOUGHT: Suppose peas are planted in Indiana on May 1. If the peas need 1200 growing degreedays before they can be picked, and if the average maximum temperature for May and June in 80°F and the average minimum is 60°F, on about what date will the peas be ready to pick? (Assume a base temperature of 55°F) 
Mean Annual Heating degree days over the U.S. in thousands of °F
