Average rainfall in Japan 2009-2018

In 2018, the annual average rainfall in Japan amounted to around 1.76 thousand millimeters. Figures increased compared to about 1.59 thousand millimeters in the previous year. Most of the rain fell during the rainy season, which is the time of year when most of a region's average annual rainfall occurs.

Seasonal rainfall

In most of Japan, the rainy season lasts from early June to mid-July. In the southernmost prefecture Okinawa, it roughly starts a month earlier, while the northernmost main island Hokkaido is less affected. Heavy rainfall can cause floods, which can lead to landslides and mudflows in mountainous areas. In 2018, flooded houses accounted for the highest number of damage situations in natural disasters. Furthermore, heavy rain and floods are often caused by typhoons, which develop over the Pacific Ocean and regularly approach the archipelago between July and October. Since the number of typhoons has increased in recent years, the amount of damage caused by floods grew as well.

Climate change

Climate change has affected Japan in recent years, resulting in increased rainfall and an increase of the average annual temperature in Tokyo. These weather changes can intensify natural disasters such as heavy rain and typhoons. In recent years, Japan ranked among the countries with the most natural disasters. To counter global warming, Japan aims to reduce greenhouse gas emissions by increasing its renewable and nuclear energy share.