Effects of Outdoor Conditions and Heating and Cooling Degree-Days on Climate Change

Purpose: This study investigates the effects of the outdoor conditions and heating and cooling degree-days on climate change. Accurate climate data is crucial for energy-consumption assessments and energy-saving solutions. To this end, this study examined historical weather data to investigate the changes in dry-bulb temperature and the trends in heating and cooling degree-days. Method: Dry-bulb temperature data for 17 cities in South Korea were collected from the weather data service of Korea Meteorological Administration. Data spanning from January 1, 1984 to December 31, 2023 were evaluated, and the missing data were interpolated using linear methods. Heating and cooling degree-days were then calculated using the degree-days method by applying a consistent base-temperature across decades and cities. Result: The results indicated a rise in the average annual dry-bulb temperatures across all cities, particularly during 2010s and 2020s. Analysis of the moving average temperatures by season showed that, except for a few years, the moving average temperatures for spring, summer, and autumn have consistently increased. The cooling degree-days increased significantly, particularly in Jeju, while the heating degree-days decreased significantly, such as in Cheongju. These trends suggest that relying on outdated climate data could lead to miscalculations in building energy consumption, which necessitates the use of recent data for accurate energy analysis and capacity planning.