Smart planning of outdoor sports tournaments using environmental heat measurements

Japan's school tennis championships often take place during the hot summer months, presenting a challenge for organizers who must balance player safety and tournament completion. To address this issue, researchers at Doshisha University developed a framework for evaluating high-heat conditions and estimating tournament availability.

They used wet-bulb globe temperature (WBGT) measurements, a widely accepted indicator of heat stress, to determine safe playing hours. The study analyzed over 119,000 hourly WBGT observations from 2018 to 2022 at 11 Japanese meteorological stations. By setting hours with a WBGT below 28°C as low-risk operational time, the researchers converted these hours into tournament indicators like feasible tournament days and match counts.

Using the 2025 Inter-High School Athletic Meet as a benchmark, the team modeled three scheduling options: standard 9 a.m. to sunset, early-morning, and nighttime formats. Their analysis showed that changing playing hours had a more significant impact on low-risk hours than altering tournament dates. The nighttime and early-morning formats increased the likelihood of WBGT remaining below 28°C by 46% and 36%, respectively.

Applying changes to both tournament dates and playing hours added up to 0.8 additional days of low-risk playing time over a seven-day tournament period. The researchers concluded that directly considering operational margins and making adjustments to tournament schedules, dates, time of day, locations, number of courts, and match formats could help protect players' lives and support the sustainable hosting of tennis tournaments.