Does weather really dictate running performance?

It’s marathon season! Which means everyone with a race on the calendar is fixated on one thing, and one thing only: The weather.

That’s right. Out of all the things you can and can’t control on race day, obsessively checking and rechecking the weather seems to be a runner’s favorite past-time. As a running coach, I’ve heard all sorts of theories on “the best weather for running,” ranging from cold-weather enthusiasts to those who thrive off sunny skies. But it made me wonder: what’s actually the best weather for running a marathon?

A 2020 study published in Medicine & Science in Sports and Exercise analyzed meteorological data for 1258 races — from the marathon, to the 50k, to the 5k and the 3000m steeplechase — held between 1936 and 2019 across 42 countries, enabling analysis of 7867 athletes. Through machine learning, it concludes that a Wet-Bulb Globe Temperature of between 10 and 17.5 degrees Celicus — or 50-63.5 degrees Fahrenheit — increased the likelihood for peak performance. For every degree outside these optimum conditions, performance declined by 0.3-0.4 percent.

A different study published more recently in Frontiers of Physiology analyzed data from the Berlin Marathon results over the last 45 years, and found that temperatures greater than 15 degrees Celsius (59 degrees Fahrenheit) and higher precipitation levels impaired performance of master marathoners.

So, what’s the moral of the story? While you can’t guarantee a perfect weather day, if your heart is set on a PR, you can schedule your next race strategically. Pick a marathon in a specific location and at a specific time of year to increase your chances of waking up to good weather. While you’ll probably still obsess over your weather app in the weeks before the big day, at least now you can do so with a little more science on your side.