Tokyo has recorded 34 consecutive days without rain, marking the longest dry spell since records began in 1886. The extended period of cloudy weather has significantly reduced sunshine hours, impacting the sweetness and harvest timing of crops. Concerns have also been raised about the potential health effects of insufficient sunlight, including issues related to sleep and fatigue.
According to the Yomiuri Shimbun, Tokyo experienced its first day without rain on August 27, continuing through September 29. This record includes days with only minimal rainfall. The previous longest streak was 33 days, from June 27 to July 29, 2019.
The prolonged dreary weather is attributed to a combination of meteorological factors. The Nikkei reported that Typhoon No. 24, which lingered south of Japan, transformed into a low-pressure system, leading to persistent rain as it interacted with the autumn rainy season front and moist air. In early September, rainfall in the Kanto region, including Tokyo, and in Nagano and Yamanashi prefectures reached approximately 3.6 times the average for that period. During Japan's autumn holiday, Silver Week (September 19-23), heavy rain also fell due to the influence of Typhoon No. 25.
With the ongoing rain and cloudy days, sunshine hours have drastically decreased. The Japan Meteorological Agency reported that from September 1 to 20, Tokyo's sunshine hours totaled just 25.2 hours, or 29% of the average. In contrast, Nagoya recorded 45.1 hours (41% of average), while Kumagaya in Saitama Prefecture, known for its heat, had only 24.4 hours (27%).
The impact on crops is already evident. The Minami-Shinshu Agricultural Cooperative in Nagano Prefecture told the Nikkei, "The prolonged rain has caused fruits to absorb more moisture, resulting in lower sweetness levels for grapes and pears at harvest time." The harvest of Shine Muscat grapes, which are picked based on sweetness standards, has also been delayed.
The autumn foliage season may also be affected. Koide Dai, a senior researcher at the National Institute for Environmental Studies, told the Nikkei that the lack of sunlight could delay the peak of fall colors and result in less vibrant foliage.
Concerns about the health impacts of reduced sunlight are growing. Katsuya Morishita, director of the Morishita Clinic in Shinagawa, Tokyo, noted an increase in patients reporting fatigue and lethargy compared to previous years. He explained that reduced exposure to sunlight can disrupt the body's internal clock, affecting sleep patterns.
There is a possibility of continued rain in the coming days. According to the Yomiuri, Typhoon No. 26 weakened on the morning of September 29 and is moving northeast over the southern seas of Japan. It is expected to approach the Izu Islands around October 1 before moving out to the eastern seas of Japan, potentially transforming into a temperate low-pressure system by October 2.
* This article has been translated by AI.
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