The Japan Meteorological Agency announced June 20, 2026, that the Hokuriku region and southern Tohoku have entered the rainy season [1].
This shift in weather patterns marks the official start of the annual monsoon period for these areas, affecting agriculture and disaster preparedness in the Japan Sea coastal regions and prefectures including Fukushima, Yamagata, and Miyagi [1].
According to the agency, the onset of the rainy season in the Hokuriku region occurred nine days later than the average year [1]. When compared to the previous year, the rainy season in Hokuriku began approximately 29 days later [1].
In southern Tohoku, the rainy season began eight days later than the historical average [1]. However, this onset was three days earlier than the start date recorded for the same region last year [1].
"The Japan Meteorological Agency announced a short while ago that the Hokuriku region and southern Tohoku are believed to have entered the rainy season," the agency said [1].
The delayed start in Hokuriku is particularly significant given the nearly one-month difference compared to the previous year. Such fluctuations in the timing of the rainy season can impact crop cycles and water management systems across the archipelago.
“The rainy season began more than a week later than average for the Hokuriku region and southern Tohoku.”
The significant variance in the start of the rainy season, particularly the nearly 30-day delay in Hokuriku compared to last year, indicates unstable seasonal transitions. Because the rainy season is critical for Japan's rice cultivation and water reservoirs, these delays can disrupt agricultural timelines and increase the risk of concentrated heavy rainfall if the season compensates for its late start with higher intensity.
