Over the years, electricity demand has increased significantly due to the demographic and industrial growth. Furthermore, climate change concerns have forced the electric power system to be restructured. On the one hand, the system has been restructured using renewable resources for power generation; on the other hand, transmission lines can be thermally constrained, and this leads to inadequate power transmission capacity on existing transmission lines. When these types of restrictions occur, the cost of energy increases because more generation is needed to meet demand and losses along the transmission line. This problem can be mitigated by upgrading overhead transmission lines with high thermal resistance conductors, but this is costly. Therefore, using predictive models based on time series to analyze the thermal behavior of overhead transmission and distribution lines is necessary in order to make technical decisions regarding power dispatches and contingencies in case of fortuitous events. This paper presents a prediction model for ampacity and conductor temperature of a 110 kV power line in the northern region of Colombia, considering the uncertainty of electrical demand, ambient temperature, wind velocity, and solar radiation by applying the IEEE 738 standard.