Extreme heat swept across Japan on Wednesday, triggering heatstroke alerts in 25 prefectures as temperatures peaked at 38.1C [1].
The scale of the heat wave has forced a shift in labor practices, particularly in agriculture, where workers are facing life-threatening conditions during peak daylight hours.
Data from 914 observation points showed that 737 locations, approximately 80% [1], recorded "midsummer days" with temperatures of 30C or higher. While some reports estimated the percentage of midsummer days at approximately 70% [2], the higher figure reflects the broader reach of the heat wave. The peak temperature of 38.1C [1] was recorded in Iida City, Nagano Prefecture, and Saijo City, Ehime Prefecture.
In Tokyo, the heat resulted in 104 people being transported to medical facilities due to heatstroke [1]. Local governments have responded by issuing alerts and urging the use of protective gear and reduced working hours.
Agricultural workers are increasingly relying on technology to survive the shifts. In Hokuto City, Yamanashi Prefecture, one worker said the perceived temperature feels close to 40C when operating machinery on steep slopes.
Shigeki Mochizuki, representative of the Mochizuki Agricultural Center, said that if there is no wind, grass-cutting work is canceled from the afternoon. He said that in August, work is only permitted in the morning. Regarding the heat, Mochizuki said it is abnormal—even within his 50 years of farming experience—and feels painful.
Experts suggest that the intensity of these weather events is linked to broader environmental shifts. A meteorology expert said the intense heat is a disaster and that global warming is one of the causes, requiring preparations to protect lives [2].
“The perceived temperature feels close to 40C.”
The convergence of record-breaking temperatures and the failure of traditional labor schedules indicates that Japan's agricultural sector must fundamentally adapt to a new climate reality. The reliance on cooling technology and the forced cessation of afternoon work suggest that midsummer heat is no longer a seasonal peak but a systemic risk to food production and worker safety.
