If this information was posted elsewhere in this thread, I apologize. I found an example of an urban gondola system in a warm weather climate. In La Paz Bolivia, there is a 6 line (more lines to open in in the future), 20 station gondola system built by
Doppelmayr and looks to have the same cars as Disney is using. The La Paz cars have solar panels but only for lights and wifi. The average temperature in Bolivia in July is 86 degrees. In the 141 reviews on TA, only one review mentioned anything about the cars being hot and that was only in the mornings when the sun was shining directly into the car. My belief is that due to the short amount of time between stations, there isn't enough time for heat to build up in the cars. The La Paz system is a huge success on several fronts. The La Paz system is also very safe with no operational mishaps to date.