It's the One Factor Runners Can't Control. It's Wreaking Havoc on Marathons.

"Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. When John Pitzel started the 2025 Tokyo Marathon, he knew that it was going to be hot. Tokyo is typically 50 degrees in early March, but on March 2, the temperature hit 68 degrees-perfect weather for a stroll but very warm for a marathon, especially for athletes who had trained through the winter to be there."

"He has run 13 full marathons and 199 half-marathons in all kinds of weather and has led pace groups in some of those marathons for the past five years. He knew that he could finish if he just ran a bit slower than normal. But he didn't expect for the race's aid stations to stop handing out water, especially because the runners were not allowed to carry their own hydration bottles."

Temperatures at the 2025 Tokyo Marathon reached 68°F, much higher than the typical early March 50°F, creating dangerous conditions for athletes who trained through winter. An experienced 62-year-old runner planned to run slower to cope but encountered halted aid stations and a prohibition on personal hydration bottles. Strict cutoff times removed slower runners from the course, leaving one competitor with cramps and dehydration and facing snow the next day. Climate change is increasing the frequency and severity of atypical heat events, reducing cities suitable for major marathons and complicating race planning and safety protocols.

Read at Slate Magazine