Conclusion: Japan’s warmer summers limit outdoor work

For workers who can’t use Japan’s many air-conditioned spaces — construction workers, delivery drivers, farmers and more — even a range of gadgets like fan-cooled jackets aren’t necessarily enough to help them survive the increasingly hot summers. That leaves companies in a difficult position as they try to balance productivity with safety.

An example is one of the most famous construction projects in Japan, located on an artificial island in Osaka Bay.

After record-high temperatures last summer, a statement from the Kansai branch of the National Federation of Construction Workers’ Unions (Zenkensoren) expressed concerns that “there were frequent cases of people being taken to hospital with heatstroke” at the 2025 Osaka Expo construction site on Yumeshima Island. NHK reported eight suspected cases of heatstroke at the expo in the six months to September 2023.