Tokyo recorded rain on 34 consecutive days, the longest uninterrupted stretch in records dating to 1886, according to the Japan Meteorological Agency. The run surpassed the previous mark of 33 days set between June 27 and July 29, 2019.
The unusually persistent rain extended well beyond the Japanese capital's typical early-summer rainy season. Regular downpours continued through the summer, and the wider Tokyo region also experienced flooding. By Monday, central Tokyo had received 629 millimetres of rain during September, nearly three times the normal amount for the month.
That total was closing in on the city's September record of 670.9 millimetres, set in 1958. The consecutive-day record and the monthly accumulation measure different aspects of the wet spell, but together they show how persistent and substantial the rainfall had become.
Japan Meteorological Agency official Masayuki Kyoda attributed part of the month's weather pattern to El Niño, which involves unusually warm conditions in parts of the Pacific Ocean and can alter winds, air pressure and cloud formation. He also said autumn rain fronts had remained in place longer than usual because a Pacific high-pressure system was lingering.
The agency stopped short of assigning the 34-day sequence directly to climate change. Weather records describe what happened, while attributing a particular episode requires a separate analysis of how likely it would have been under different climate conditions. Kyoda nevertheless pointed to a Japan Meteorological Agency report from the previous year that found global warming was influencing the country's weather over the long term, including through increased precipitation.
Warmer air can hold more moisture, which can create conditions for heavier rainfall. El Niño can also shift rainfall patterns across regions, bringing wetter conditions to some locations and drought to others. Those broad mechanisms provide context for Tokyo's weather, but they do not by themselves establish the cause of every rainy day in the streak.
The record is notable because Tokyo's observations span 140 years, allowing the latest sequence to be compared with many decades of changing weather. The former 2019 mark occurred during the city's normal rainy-season period, whereas the new streak continued into late September after repeated summer downpours.
The agency's measurements give authorities and residents a clear picture of accumulated rainfall as they monitor flood and drainage risks. They also add a new data point to Japan's long climate record. Whether the streak becomes part of a broader shift in seasonal rainfall will depend on analysis across many years, not this episode alone.
