Compared to conventional porcelain insulators, polymeric insulators are easier to work because of their lightness, and have better withstand voltage performance under discharge, rain, and contaminated conditions due to their higher hydrophobicity. Therefore, their application is expected to reduce the size and cost of power distribution facilities, so the introduction of polymeric insulators is being promoted in Japan. On the other hand, the use of polymeric materials for the outer coating raises concerns about their deterioration over time, and clarifying the long-term performance in the contaminated and humid environment unique to Japan is an important issue for practical application. To evaluate the long-term weather resistance of polymeric insulators for distribution lines, Tohoku Electric Power Network Co., Inc. has conducted field tests in the coastal areas along the Sea of Japan. In this study, we developed prediction models of leakage current generation based on meteorological conditions using feed-forward neural networks and verified the effectiveness of the models. And we also evaluated meteorological factors which affect the prediction results with the neural network models.