Heating engineers relate each day’s temperatures to the demand for energy to heat/cool buildings. They developed the concept of degree days which can be used to relate how much more or less you might spend on heating or air conditioning.
This graph illustrates the difference between heating and cooling requirements in Bundaberg Australia based on a reference temperature of 18 degrees centigrade.
The data presented is the mean temperature for Bundaberg Australia sourced from the Australian Bureau of Meteorology and averaged over the range of available records.