 Both Gatun Lake and Madden Lake (also filled with water from the Río Chagres) provide hydroelectricity to the former Canal Zone area.The Río Chepo, another major source of hydroelectric power, is one of the more than 300 rivers emptying into the Pacific.Under the Köppen climate classification, Panama City has a tropical savanna climate (Köppen "Aw"), a little drier than a tropical monsoon climate.