Tokyo has endured more than a month of uninterrupted wet weather, with central parts of the Japanese capital recording rain for a 34th consecutive day on Tuesday, September 29, setting a new record.
Rain has been observed at the Japan Meteorological Agency’s central Tokyo site every day since August 27. The latest streak surpassed the previous record of 33 consecutive rainy days, which ran from June 27 to July 29 in 2019. Records in Tokyo date back to 1886.
September rainfall nears historic levels
The prolonged spell has made September unusually wet. Central Tokyo had received 629 millimeters of rain through Monday, nearly three times the normal amount for the entire month and close to the September record of 670.9 millimeters set in 1958.
The heaviest rainfall during the current streak came on September 21, when 156 millimeters fell in central Tokyo. The wet weather has extended beyond the capital, with rain affecting areas from Hokkaido to Kyushu as a stationary autumn rain front stretches across the country. In Echizen, Fukui Prefecture, more than 30 millimeters of rain was recorded in a single hour early Tuesday.
Sunshine hours have also been lower than usual, prompting weather officials to advise farmers to take extra care with crops.
Autumn rain front keeps conditions unsettled
Weather officials have linked the prolonged conditions to a combination of an autumn rain front, low-pressure systems and tropical weather near Japan. A Japan Meteorological Agency official also said this month’s unusual weather pattern was partly influenced by El Niño, while a Pacific high-pressure system has remained in place longer than normal.
Although officials have not directly attributed the 34-day streak to climate change, the weather agency has previously found that global warming is affecting Japan’s long-term weather patterns, including by increasing precipitation.
The unsettled conditions are expected to continue. Rain is forecast to persist through Thursday in parts of eastern Japan, including Chiba and Kanagawa prefectures, where recent heavy rainfall has already left some hillsides unstable and damaged levees. Authorities have warned that even relatively small amounts of additional rain could increase the risk of landslides and other disasters.
A tropical storm south of Japan is also expected to move closer to the Izu Islands, bringing the threat of strong winds, high waves and rough seas as the rainy stretch continues.
