Trends in the number of lightning days at major domestic sites based on the observation record of the Japan meteorological agency

The damages caused by lightning on modern electrical and electronic devices that have low resistance against external noise tend to increase yearly. In recent years, though an increase in the frequency of lightning strikes due to global warming is often reported, a demonstration with credible data has not yet been performed. We have consolidated the data on the annual lightning days in each region for approximately the last 100 years published together with other weather data from the website of the Japan Meteorological Agency, and we report the study results.