Warm Air Temperatures Generate Home Runs

Significance Statement This study examines the impact of rising temperatures on home run frequencies in Japan’s Nippon Professional Baseball (NPB). Building on previous research from Major League Baseball (MLB) in the United States, we found that higher temperatures correlate with more home runs, but only in outdoor stadiums, which supports the idea that temperature affects ball flight by reducing air density. Our findings are consistent over different time periods and suggest that climate change could increase home run numbers. However, no clear trend of more home runs due to recent warming was observed. Further research is needed to understand the factors affecting this phenomenon in different stadiums. This work underscores the broader impacts of climate change on various aspects of society, including sports.