The weatherability evaluation with outdoor exposure test for building exterior materials is the most essential. The most standard outdoor exposure test site throughout the world is considered to be South Florida, US. Also the accelerated weathering test that gathers plenty of sunlight in dry condition is carried out in Arizona. The investigation into the actual conditions of these sites was held. The actual conditions of the tests and weather conditions in both sites have been grasped. Furthermore, outdoor exposure tests in Florida and Miyako Island, Japan had been carried out. All evaluated powder coating had been more notably deteriorated in Miyako than in Florida.