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

The warming climate is forcing marathons to consider changes to keep runners cool. Paul Grinvalds, a marathoner who has completed 114 races across all 50 U.S. states, struggles in temperatures exceeding 60 degrees Fahrenheit (15.5 Celsius). Most runners, including Grinvalds, are stubborn and will still attempt to complete a race even in hot conditions, potentially leading to a painful and dangerous experience.

Marathon organizers are responding to climate change by adjusting race dates, starting times, and offering participants the option to cut races short. For example, the Twin Cities Marathon in Minneapolis-St. Paul has shifted its date later in October starting in 2027, moving it from the first Sunday of the month. The Sioux Falls, South Dakota, marathon moved its race from August to September after cancellation in 2024 due to hot conditions.

Other races, such as the Air Force Marathon in Dayton, Ohio, the Little Rock Marathon in Arkansas, and the Long Beach Marathon in Southern California, have also adjusted start times to earlier in the day. In Los Angeles, warm conditions led to a new option for runners to stop after 18 miles and still receive a finishers medal. Despite the measure's popularity, it generated online criticism.

The warming climate, primarily caused by the burning of fossil fuels like coal and gasoline, is making conditions more challenging for marathons. By 2045, optimal conditions for recreational runners may be rare at 46 out of 51 U.S. marathons, according to a study by Climate Central. Climate change is already affecting marathons, as indicated by the World Meteorological Organization's forecast of a global temperature rise of over 1.5 degrees Celsius (2.7 degrees Fahrenheit) between 2025 and 2030.

Experts warn that marathons and other outdoor sports face increasing challenges, potentially pushing participants to exercise indoors or opt for less strenuous activities.