The warming climate is forcing marathons to consider changes to keep runners cool

IOWA, USA: Paul Grinvalds has completed 114 marathons in all 50 states, but he still wilts when he races in temperatures beyond 60 degrees Fahrenheit (15.5 Celsius).
It’s the same for most runners, as the body can’t cool down during exertion, and heat makes that even harder.
“One thing about marathoners is typically we’re kind of stubborn,” said Grinvalds, 68, from West Des Moines, Iowa, who finds even temperatures in the 50s F (10 C) a bit warm. “So if we have a goal and it’s hot, a lot of times we’re still going to try to do that goal, which is just stupid because you’re almost guaranteed to have a very painful experience.”
Such an experience can also be dangerous, a reality that marathon organizers are having to confront as climate change, caused mostly by the burning of fuels like coal and gasoline, pushes temperatures up.

To improve the chances of having the 26.2-mile (42-kilometer) race in cooler weather, organizers are shifting race dates, starting earlier and even giving options for participants to cut their runs short.
Starting in 2027, the Twin Cities Marathon in Minneapolis-St. Paul will shift its more than 40-year tradition of holding the race on the first Sunday in October to later in the month.

That decision comes after cancelation of the marathon in 2023 because of record heat and humidity, and starting temperatures near 70 F (21 C) for the 2025 race.
Organizers of the Sioux Falls, South Dakota, marathon last year similarly moved their annual race from August to September after canceling the 2024 race due to hot conditions. And other races, including the Air Force Marathon in Dayton, Ohio, the Little Rock Marathon in Arkansas, and the Long Beach Marathon in Southern California, all moved their start times