One of the ways to improve electric power transmission systems is to efficiently utilize the capacity of the existing power circuits. That can be achieved by increasing the thermal ratings of the transmission lines. In this research, weather-based rating approaches were studied. Static thermal rating (STR) strategies (probabilistic and seasonal) and a new dynamic thermal rating (DTR) approach based on numerical weather prediction (NWP) were evaluated. The results demonstrate that the DTR approach allows better line utilization compared to STR methods. It was also shown that the postprocessing technique called model output statistics (MOS) can significantly reduce errors in numerical weather simulation, improve the accuracy of the DTR system, and reduce the risks of line overheating. Efficient data management, processing, and visualization were investigated to fully utilize the potential of an advanced DTR system. Applications of the latest web-based technologies, geospatial databases, and 3D visualization techniques are presented.