Running fans hoped to see history made in Berlin on Sunday, when Eliud Kipchoge, widely regarded as the world’s top marathoner, set out to break a world record. But the Kenyan, who took gold in the men’s marathon in Rio, fell 35 seconds short of making history.

His brush with greatness would not be notable but for the circumstances of the race. Kipchoge was hampered by heat, humidity and rain, symptoms of a problem that’s growing worse by the day — climate change.

Historically, Berlin has boasted uncommonly favorable conditions — a flat course, cool weather and overcast skies. The German capital was the scene of seven of the ten fastest marathons ever run, including the world record, claimed by Dennis Kimetto of Kenya, who completed the 2014 Berlin marathon in 2:02:57. Kipchoge, while he placed first on Sunday, failed to catch Kimetto’s ghost, clocking in at 2:03:32.

“The conditions were not friendly because of the rain,” Kipchoge told reporters after the race. He gave up hope of a record-setting performance after just five kilometers. “That’s when I realized that the world record was not possible.” Perhaps more troublesome than the rain were the heat and humidity. At the start of the race, it was unusually warm and oppressively humid.

A 2007 study showed that the fastest marathoners run about 1 percent slower for every 9 degree temperature increase above 40 degrees F. The average starting temperature of the Berlin marathon is 50 degrees F. At the start of Sunday’s race, the temperature was 58 degrees F, meaning Kipchoge could expect to run almost 1 percent slower than he would have in a typical year.

According to the study, the extra heat added around 70 seconds to Kipchoge’s total time. He was just 35 seconds shy of a new world record.

Of course, Kipchoge also had to contend with humidity, which makes heat even worse. Under dry conditions, sweat evaporates, cooling off the body. When it’s humid outside, sweat clings to the skin and athletes stay warm. On top of that, rain made roads slippery, slowing down runners even more. If it had just been a little cooler or a little dryer, Kipchoge might have made history.

Here’s where climate change comes in. The Earth has warmed by around 2 degrees F in a little more than a century. Rising temperatures have caused the atmosphere to hold more moisture, producing more humid weather. The greater volume of water in the atmosphere has also led to more frequent and intense rainfall in many parts of the world, including Germany. All of this put together is enough to slow down even the most finely tuned human machine.

Kipchoge said he still has his sights on the world record, but he is running out of time. Marathoners tend to peak in their late twenties and then see a gradual decline in performance. At 32, Kipchoge was the oldest runner to finish in the top ten at Sunday’s marathon. He is in the twilight of his reign as the world’s greatest distance runner. He won’t make too many more attempts at a world record.

Marathon running is a matter of both luck and preparation. Anyone trying to run the fastest race of all time needs to catch every break. They need to walk up to the starting line full of confidence and free of injuries. They need a flat course and cool, crisp weather. Rising temperatures mean that organizers will need to plan races for later in the fall and earlier in the spring. This is crucial for fast courses, like the London, Chicago and Berlin marathons, where elite runners attempt to break records.

When asked about the scheduling or races, a spokesperson for the Chicago marathon said organizers “consistently target the early October timeframe given the global running and Chicago calendar of events,” but she made no mention of climate change. Spokespeople for the London and New York marathons gave similar answers. Organizers of the Berlin marathon did not respond to a request for comment.

If organizers continue to overlook the effect of rising temperatures in race planning, there will be fewer records broken at marquee races, like Berlin. That’s sad for Kipchoge, who has dedicated his life to testing the limits of the human body, and for the fans who can only wonder what might have been.

Jeremy Deaton writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture. You can follow him @deaton_jeremy.