Meteorological conditions exert influences on sport performances via complex processes. Previous studies conventionally investigate the effects of weather conditions on marathon performance by following events held at the same places, which brings large uncertainties due to the changed participants. Via following each athlete to eliminate these uncertainties, we show that elite athletes’ marathon-running performance tends to monotonically worsen as ambient temperature rises except when it is extremely cold based on the best 16 athletes from each of the sex continents. It worsens by 0.56 (0.39 for men and 0.71 for women) min/°C when it rises beyond 15 °C. Theoretical analysis based on global marathon performance and weather observation datasets shows that more than half of this effect is mediated by reduced oxygen partial density as warmer temperature expands air and increases vapor pressure for both the men and women athletes, which is confirmed by the methods of Baron–Kenny. This atmospheric thermodynamic mechanism has not been emphasized previously. We also show that world-top athletes’ marathon performance approximately linearly worsens as ambient pressure decreases and slightly worsens as relative humidity rises if not extremely wet. These results substantially differ from the previous ones following the events instead of each athlete. Multi-variable changes in climate system are projected to slow Olympic marathon athletes by 2.51 and 1.06 min by the end of the 21^st century in relative to 2020 under the high and intermediate emission scenario, respectively. Therefore, future progression of marathon performance is likely to be substantially slowed or even halted by climate changes without efficient greenhouse gas mitigation.

气象条件通过复杂的过程对运动表现产生影响。以往的研究通常通过跟踪在同一地点举行的赛事来研究天气条件对马拉松成绩的影响，由于参与者的变化带来了很大的不确定性。通过跟踪每位运动员以消除这些不确定性，我们根据来自各大洲的 16 名最佳运动员的数据显示，随着环境温度的升高，精英运动员的马拉松成绩往往会单调恶化，除非天气非常寒冷。当温度超过 15°C 时，温度会恶化 0.56 分钟/°C（男性为 0.39，女性为 0.71）分钟/°C。基于全球马拉松成绩和天气观测数据集的理论分析表明，这种效应的一半以上是由氧气部分密度降低介导的，因为气温升高使空气膨胀并增加了男女运动员的蒸气压，这一点已通过以下方法得到证实：巴伦-肯尼。这种大气热力学机制以前没有被强调过。我们还表明，世界顶级运动员的马拉松成绩随着环境压力的降低而近似线性恶化，并且随着相对湿度的上升（如果不是极度潮湿）而略有恶化。这些结果与赛事之前的结果有很大不同，而不是每个运动员。在高排放情景和中排放情景下，预计到²¹世纪末，气候系统的多变量变化将使奥运会马拉松运动员的速度比 2020 年分别慢 2.51 分钟和 1.06 分钟。因此，如果不有效缓解温室气体排放，未来马拉松成绩的进步可能会因气候变化而大幅放缓甚至停止。