The Japan Meteorological Agency announced that the Tokai and Kanto-Koshin regions entered the rainy season on June 7, 2024 [1].
This seasonal transition marks the beginning of the annual rainy period for eastern Japan, influencing agricultural cycles and daily transportation for millions of residents in these densely populated areas.
The agency determined that the regions had met specific precipitation and humidity criteria required to officially declare the start of the season [2]. According to the agency, the arrival of the rainy season in the Tokai region was one day later than average [1]. In contrast, the Kanto-Koshin region entered the season at a timing consistent with average years [1].
"Tokai and Kanto-Koshin regions entered the rainy season today (7th), and eastern Japan has also entered the rainy season," the Japan Meteorological Agency said [3].
Weather forecasts indicate a period of instability for the immediate future. The agency said that both regions are expected to experience a high frequency of cloudy and rainy days over the next seven days [1].
"Both regions are expected to have many cloudy and rainy days for the next week," the Japan Meteorological Agency said [4].
Local authorities typically monitor these transitions closely to manage potential flooding and landslide risks that accompany the heavy rainfall characteristic of the Japanese rainy season.
“The Tokai and Kanto-Koshin regions entered the rainy season on June 7, 2024.”
The official declaration of the rainy season, or 'tsuyu,' provides a critical signal for infrastructure management and agriculture in Japan. Because the Kanto-Koshin region, which includes the Tokyo metropolitan area, is entering the season on schedule, the impact on urban logistics and public transport is expected to follow historical patterns. However, the slight delay in the Tokai region may shift the timing of peak rainfall, requiring adjusted vigilance for flood-prone areas.
