Runners face a warmer reality on race day
As tens of thousands of runners line up for the New York City Marathon this Sunday, many will contend with weather that’s warmer than what researchers consider optimal for peak performance. The window scientists identify as ideal for marathon running—roughly between 39 and 50 degrees Fahrenheit (4–10°C)—is narrowing as the planet warms. This shift poses a challenge not just for elite athletes chasing records, but for recreational runners striving for personal bests.
Climate change reshapes the odds of perfect race-day conditions
A new analysis from Climate Central—a nonprofit, science-focused research group—finds that global warming will make ideal marathon weather increasingly rare at many events worldwide. Among 221 marathons studied, 86% are forecast to have a diminished chance of optimal conditions on race day by 2045. The impact touches all seven Abbott World Marathon Majors, including New York City and Boston, signaling a broad shift in the sport’s landscape.
A shift across major venues
For elite male runners, Tokyo currently offers some of the best odds for ideal conditions, but the climate analysis warns that even this benchmark is deteriorating. Heat waves—already recorded in this year’s Tokyo and Berlin marathons—are becoming more likely due to climate change, pushing race-day temperatures beyond the optimal range for high performance. By 2045, the likelihood of an ideal weather day for elite men in Tokyo drops from 69% to 57%. In Berlin, the odds for elite women fall from 40% to 29%.
Who is affected and how athletes adapt
Looking across 2025–2045, elite men face declining optimal-temperature odds in Tokyo, Boston, London, New York, and Berlin. Elite women are confronting reduced chances in London, New York, Chicago, Berlin, and Sydney. While elite female runners are often described as more resilient at higher temperatures, Climate Central notes that even these athletes will not be immune to the trend toward less favorable race-day conditions in the coming decades.
Former marathon world record holder and champion Catherine Ndereba underscored the changing realities, saying, “Climate change has altered the marathon. Dehydration is a real risk, and simple miscalculations can end a race before it begins.” She also highlighted the need for athletes to rethink routines—hydration, nutrition, and overall training strategies—so they can adapt to hotter, more humid conditions that are increasingly common on race days.
What organizers and runners can do
Climate Central suggests practical steps for race organizers, including scheduling starts closer to sunrise to exploit cooler early-morning air. But they stress that long-term safeguarding of marathons depends on meaningful climate action and reducing fossil-fuel use. The goal is not only to protect historical performance but also to ensure safety, inclusivity, and the continued enjoyment of road racing for runners of all levels.
Looking ahead to the future of the sport
As cities around the world host iconic races, the evolving climate is forcing organizers to weigh comfort, safety, and performance in equal measure. The NYC Marathon, known for its dynamic course and massive crowd support, embodies the broader challenge: how to preserve the thrill and achievement of distance running when the climate is shifting beneath every stride.
Ultimately, the takeaway is clear: without aggressive climate action, the odds of hitting ideal race-day conditions will continue to decline. Runners, teams, and organizers will need to adapt—embracing smarter hydration strategies, revised training plans, and thoughtful scheduling—to keep the marathon accessible and competitive in a warming world.
