Refining climate zoning in North Africa: A 30-Year analysis of heating and cooling degree days for energy planning and adaptation

This research investigates the spatial variability of heating degree days (HDD) and cooling degree days (CDD) to advance climate zoning across North Africa. Using 30 years of high-resolution meteorological data (1989–2019) from 108 weather stations in Egypt, Libya, Tunisia, Algeria, Morocco, and Western Sahara, HDD and CDD values were calculated for six base temperatures (HDD: 12 °C–22 °C; CDD: 18 °C–28 °C) using NASA/POWER data. The findings reveal substantial climatic and topographical influences on thermal energy demands. Northern regions, particularly high-altitude locations like Bordj Bou Arreridj, Algeria, exhibited the highest HDD values, reaching 2932 at 18 °C, while southern desert areas, such as Adrar, Algeria, demonstrated extreme CDD values, peaking at 3169 at 18 °C. GIS-based spatial interpolation methods enhanced visualization, delineating detailed sub-classifications within the Köppen-Geiger framework, increasing spatial resolution from 12 321 km2 to 3025 km2. For example, Algeria alone expanded from five to 35 sub-classifications. These refined zones reveal critical differences in energy demand, with northern cities requiring up to 10 times more heating energy, while southern cities demand up to eight times more cooling energy compared to coastal zones. The results provide an essential basis for updating regional building codes and optimizing HVAC designs, supporting climate adaptation and energy efficiency strategies tailored to North Africa’s diverse climatic zones. By enhancing spatial resolution and refining classifications, this research transforms energy planning and thermal regulations in the region.