A degree-day is a unit used to measure the fuel requirements of buildings By definition, each degree that the average daily temperature is below 65F is 1 degree-day. For example, a temperature of 45F constitutes 20 degree-days. If the average temperature on January 1 was 45F and fell 3F for each subsequent day up to and including January 14, how many degree days are included from January 1 to January 14? From January 1 to January 14 degree days are included