I'd trained for a cool morning. Race day had other plans, and the only reason I finished upright was that I found out before the start line did.
Marathon training makes you obsessive about a lot of things, but for months my obsession was pace, specifically hitting a pace band I’d built around a training block full of cool, overcast mornings. Race morning, I checked the forecast the way I always do before a long run, expecting to confirm what I already assumed. Instead I got a warning I hadn’t planned for: a temperature and humidity combination well outside anything I’d trained in, climbing fast through the back half of the course, with the kind of heat index numbers that meteorologists don’t attach to distance races for fun.
I had, at that point, about ninety minutes before the gun. Enough time to make a real decision instead of a panicked one at mile fifteen when it would’ve been too late to matter.
I threw out the pace band. Genuinely threw it in the gear check bag and didn’t look at it again. Instead I ran the first two miles deliberately conservative, took every water station instead of my usual “every other one,” and made peace with a finish time that was, by my training numbers, embarrassingly slow.
It was the right call by mile eighteen, where I passed a noticeable number of runners who’d gone out on their trained pace and were now walking, some of them looking genuinely unwell, medical tents doing more business than I’d ever seen at a race before. I finished upright, slower than my training suggested I could, faster than a lot of people who’d ignored the numbers and paid for it in the heat.
A friend I ran with afterward admitted she hadn’t checked anything beyond “is it going to rain,” which had never crossed her mind as the wrong question for a summer marathon — heat index, not precipitation, was always going to be the number that mattered that day.
If you’ve got a running friend gearing up for a race, tell them to check more than just rain chance the morning of — heat and humidity have ended more marathons than weather anyone thinks to plan for, and finding out before mile two beats finding out at mile fifteen every single time. Race-day heat and humidity get their own deeper look here, for anyone plotting a race further out than mine was.