Much of Japan experienced early-summer sunshine on Sunday, though rain clouds moved in from the west and the Amami region entered its rainy season [1].
This shift in weather marks the transition toward the humid summer months, affecting outdoor activities and agricultural planning across the archipelago. The timing of the rainy season, or *tsuyu*, is critical for water management and regional infrastructure preparations [1].
In the Kanto and Hokuriku regions, residents saw a significant rise in temperature [1]. One recorded high reached 25.1°C [1]. These areas were identified as regions observing "summer days," characterized by temperatures reaching 25°C or higher [1].
Despite the warmth in the east, weather reports indicated that rain clouds began spreading from the west [3]. This system brought precipitation to western Japan and pushed the Amami Islands, located in the southern Ryukyu chain, into their official rainy season [1, 2, 3].
Local events continued despite the shifting skies. In the Kanto region, the "Meat Festival 2026 in Todoroki Ryokuchi" took place amid the sunny conditions [1]. However, some observers said it still felt "a little cold" during certain periods of the day [1].
The movement of the rain-cloud system is expected to continue influencing weather patterns as the country moves further into May [1, 3].
“The Amami region entered the rainy season.”
The simultaneous occurrence of early summer heat in the north and the onset of the rainy season in the south illustrates the complex meteorological transition Japan undergoes in May. The arrival of the rainy season in the Amami region serves as a leading indicator for the eventual movement of the seasonal rain front toward the mainland, which typically brings essential rainfall for rice cultivation but also increases the risk of flooding.
