Introduction of various heat stroke countermeasures in Saitama Prefecture

Focusing on the Climate Change Adaptation Center of Saitama Prefecture

Abstract

Due to the effects of global warming, Saitama Prefecture faces challenges related to extreme summer heat and heatstroke, with a record high of 41.1°C recorded in 2018—the highest in Japan. In recent years, the number of extremely hot days has continued to increase, and the prefecture ranks among the highest nationwide for emergency heatstroke cases. In response, the Saitama Climate Change Adaptation Center (the Prefectural Adaptation Center) has promoted research and awareness campaigns on heatstroke as part of its broader climate change adaptation efforts. The Center fulfills two main roles: collecting, organizing, and analyzing climate-related data, and providing information to local governments and residents. As a unique initiative, Saitama has also jointly established regional climate adaptation centers with municipalities, with 17 cities and towns participating as of April 2025. On the Kanto Plain, sea breeze patterns contribute to heat environment complexity. Particularly in the central region, which lies downwind of central Tokyo, high temperatures often persist in the afternoon. To monitor these regional variations, the Center developed IoT-based heat index sensors that enable real-time monitoring across multiple locations. Data analysis revealed that the northern part of the prefecture tends to experience longer durations with heat indices above 28°C compared to the south. Local governments are also taking action. For example, Kumagaya City uses digital signage for public outreach, and Fukaya City is collaborating with agri-tech companies. The Center also works with the prefectural health department to intensify public communication during heat alerts. Despite an increase in extremely hot days in 2024, the number of heatstroke-related emergency transports declined compared to that of the previous year, highlighting the impact of these initiatives. The Center will continue to work with relevant agencies to strengthen heat-adaptation measures.