Natural disasters in Japan Furthermore, typhoons are likely to approach the archipelago, usually between July and October during the peak of the typhoon season. Tropical cyclones often cause heavy rainfall and flooding.

In Japan, natural disasters can occur at any time, but September is statistically the most dangerous month due to the peak of the typhoon season and a historical legacy of major events. While typhoon season officially spans from June to early November, the most destructive storms typically make landfall in August and September. September's typhoons are particularly hazardous because they often activate "autumn rain fronts," leading to catastrophic flooding and landslides. This month also holds a somber place in Japanese history, as the Great Kantō Earthquake occurred on September 1, 1923; as a result, September 1 is now observed as National Disaster Prevention Day. Beyond typhoons, winter months (December–February) bring heavy snow-related disasters to northern Japan and the Sea of Japan coast. Earthquakes and volcanic eruptions, however, remain a year-round threat with no seasonal pattern, requiring the nation to maintain one of the most sophisticated disaster-readiness and early-warning systems in the world regardless of the calendar month.