This paper presents a methodology for integrating terrain shadows of micro-locations into building energy modeling (BEM) for topographically diverse regions. Dynamic energy simulations rely on high-resolution weather data sourced from reference locations that cover a climate zone. As soon as the micro-location of the simulated building is away from the weather reference site, topographic shading can trigger deviations. This study developed a three-dimensional reproduction of the micro-location’s surrounding terrain as a simplified ring model based on available horizon height captured from PVGIS. In a radius of 20 km, 4 Slovenian cities from the same climatic zone have been analyzed and compared with a baseline calculation. When comparing solar gains (SG) of chosen micro-locations, a tendency is noticeable—the lower the Sky-view Factor (SVF), the higher the SG deficit. Additional calculations have been conducted for different SVF/aspect ratios and used in a geographical survey. Results show that at least half of the Slovenian land surface which is inhabited by 21% of the population, has characteristics where topography influences calculated Solar Gains (SG). In those areas, the potential SG deficit is distributed from barely perceptible to more than 25% in certain areas. This approach enhances the precision of BEM in topographically varied landscapes and can inform better design and planning decisions.