Mountain Line in Missoula, Montana, is undertaking a remarkable transition from diesel-powered buses to a zero-tailpipe-emissions electric bus fleet to combat climate change and enhance air quality. The agency faced unique challenges due to the region's extremely cold weather, with temperatures dropping below -20°F and frequent snowstorms. In 2017, Mountain Line received funding to purchase Proterra battery-electric buses, but encountered range issues at temperatures as high as 20°F, prompting the integration of heated battery systems. To tackle the cold weather obstacles, a study was initiated in 2020 to evaluate the performance of electric buses in icy conditions, focusing on battery efficiency, range, and heating capabilities. By monitoring the buses with specialized software and collaborating with experts, Mountain Line ensured the reliability and efficiency of its fleet year-round. The agency also adjusted bus schedules based on weather conditions to optimize performance, with different bus models displaying varying levels of feasibility in cold weather. Furthermore, Mountain Line invested in training its team, including mechanics and drivers, on safety protocols, maintenance procedures, and energy-saving techniques to maximize the buses' potential. Despite the challenges, Mountain Line remains committed to achieving a 100 percent zero-emission fleet by 2035, highlighting the dedication to environmental sustainability and innovation in public transportation.