Japanese weather agencies forecast dangerous heat and an approaching typhoon for the Kanto region starting June 1, 2026 [1, 2].

The rapid shift from extreme heat to a tropical storm creates a high-risk window for public health and infrastructure. Residents must prepare for both heatstroke risks and potential transport disruptions caused by heavy rain and strong winds [1, 2, 3].

Forecasters expect temperatures to rise sharply on June 1. In Kiryu, the maximum temperature is forecast to reach 35 °C [1]. Some areas are expected to exceed 30 °C as early as 10 a.m. [1]. This heatwave is driven by a seasonal high-pressure ridge, leading to heat alerts being issued for 32 prefectures [2].

The weather pattern will shift as a typhoon approaches. While one source identifies the storm as Typhoon 6 [1], others identify it as Typhoon 9 [2]. The storm is expected to be closest to the Kanto region on the morning of June 2 [1, 2].

Peak impacts are forecast for June 3, with the storm bringing heavy rain and strong winds to areas including Hakone and western Kanagawa prefecture [1, 2]. These conditions are expected to modify the regional temperature significantly. By the third day of the typhoon's influence, temperatures are forecast to drop to around 21 °C [1].

Local authorities said the public should use air conditioning to manage the initial heat spike before the storm arrives [1].

“Maximum temperature forecast for Kiryu: 35 °C”

The Kanto region is facing a volatile meteorological transition where a high-pressure heatwave is being abruptly displaced by a tropical cyclone. This sequence increases the risk of flash flooding and wind damage while forcing a sharp temperature swing of nearly 14 degrees Celsius in three days, challenging both energy grids and public health readiness.