In what years did Chicago accumulate the most heating and cooling degree day units?
Thanks, Tom Kucinski Chicago- North Center
Heating and cooling degree day units are measures that indicate the departure of the day’s average temperature using a base of 65 degrees, a value where neither heating nor cooling is needed. Each degree the average temperature is below 65 is one heating-degree day (HDD) and each degree above 65 is one cooling-degree day (CDD). HDDs are summed from July 1-June 30 to define an entire heating season, while CDDs are compiled annually to capture the entire cooling season. Chicago’s current normals (1991-2020) are 5974 HDD and 1003 CDD. Since 1943, the extremes for HDDs were 7175 in the 1981-82 heating season and 4907 in 2011-12. Values for CDD range from 1352 in 1955 to 457 in 1992.