Japan will see divided weather patterns on April 15, 2026, with sunny skies in the west and rain in the east [1].
These shifting conditions may disrupt morning travel for millions of commuters in the Kanto region and pose flooding risks in the south.
Forecasts indicate that western Japan, including cities such as Osaka and Hiroshima, will experience some sunny periods [1]. A high-pressure ridge is dominating the western half of the country, which is contributing to the clearer skies in those areas [3, 4]. In Osaka, the maximum temperature is expected to reach 29 ℃ [1].
Conversely, eastern and northern Japan will remain mostly cloudy [1]. A stationary front and moist air are affecting the eastern half of the country, leading to more unstable weather [3, 4]. In the Kanto region, rainfall is likely during the morning commute [4]. The Japan Meteorological Agency said there is a risk of heavy rain in Kanto through midday [2]. Tokyo is expected to have a maximum temperature of 20 ℃ [1].
Northern regions, including Hokkaido and Tohoku, will also see cloud cover, with Sapporo forecasting a maximum temperature of 24 ℃ [1].
Conditions in the south are more volatile. While some reports suggest occasional rain and sunny periods for Kyushu, Okinawa, and Amami, other data indicates a higher risk [1, 5]. The Japan Meteorological Agency said heavy rain is expected across Kyushu, noting that a line-shaped rain band may develop in Kagoshima [5].
Local authorities are monitoring the situation in Kagoshima due to the potential for intense precipitation. The Japan Meteorological Agency said clouds will likely spread across Tokai and Hokuriku, where rain and thunderstorms are possible [2].
“Kanto is at risk of heavy rain through midday.”
The contrast between the high-pressure ridge in the west and the stationary front in the east creates a volatile weather split across the archipelago. The potential for a line-shaped rain band in Kagoshima is particularly significant, as these meteorological phenomena often lead to localized flooding and landslides, requiring heightened vigilance from regional disaster management teams.
