In order to calculate a degree day, you must first know the high and low temperatures for that day. Next, you will take an average of the 2 temperatures. If the average temperature is 65 degrees Fahrenheit or more, you should subtract 65 from the average daily temperature. If the average temperature is less than 65 degrees Fahrenheit, you should subtract the average daily temperature from 65.
Example 1:
| High Daily Temperature: | 90 |
| Low Daily Temperature: | 68 |
| Average Daily Temperature: | (90+68)/2=79 |
*Since the Average Daily Temperature is more than 65, you will subtract 65 from the Average Daily Temperature.
Degree-Days: 79-65=14
Example 2:
| High Daily Temperature: | 42 |
| Low Daily Temperature: | 22 |
| Average Daily Temperature: | (42+22)/2=32 |
*Since the Average Daily Temperature is less than 65, you will subtract the Average Daily Temperature from 65.
Degree-Days: 65-32=33