Out the door at 5:30 this morning. Sky was still doing that orange thing, crescent moon up, streets empty. One of the better-looking mornings I've had out there.
Then I started running and remembered — it's June in Florida.
6.19 miles. 10:33 pace. 1:05:17.
That looks slow. It felt slow too. But it wasn't a slow effort. It just looked like one.
The number that actually matters: dewpoint
Everyone talks about humidity like it's the only weather stat that matters for running. It's not. Humidity is relative — it tells you how saturated the air is compared to what it could hold at that temperature. Dewpoint tells you the actual moisture content in the air, period.
This morning: 71°F, 90% humidity. That works out to a dewpoint around 68°F. Anything above 65 is considered hard running conditions. Above 70 is genuinely rough. Your body cools itself by sweating — and when the air is already loaded with moisture, sweat doesn't evaporate as well. Your internal temp rises faster. Your HR climbs. Same effort, slower pace.
It's not fitness. It's physics.
The same "easy" effort that felt effortless in February now costs me a real HR penalty. The body is doing the same work — but it's spending extra budget on thermoregulation. That budget comes from somewhere. The pace is where it comes from.
I spent a long time running by pace instead of effort. Easy days felt like failure if the splits were slow. So I'd push them a little, make them "feel" like something, and then wonder why I was tired all the time. Running in Florida in the summer on pace targets built for April is how you get hurt.
Treadmill or outside — both are fine
The treadmill is a real option in summer. Climate controlled, consistent footing, you can run whenever the schedule allows. For tempo work especially, it makes sense. Your body doesn't know the difference.
But sometimes you just want to be outside. The empty street. The sky changing color. No belt humming under your feet. There's something about being out there in the dark when most people are still asleep that a treadmill can't really replicate — and I'm not gonna pretend otherwise.
The move I've landed on: treadmill when the conditions are genuinely dangerous (dewpoint 72+, feels like 95+). Outside when it's just hot and humid, which is every morning in June. You slow down. You run by effort. You pay the summer tax and keep moving.
Here's the thing about training for a specific goal: the easy days are as specific as the hard ones. A 3:15 marathon requires a certain kind of aerobic engine. You build that engine on easy days and long runs — not just tempo work. If I blow easy days by treating slow summer splits as a problem to fix, I'm undermining the base I actually need.
So yeah, 10:33 in June. The effort was right. The training effect was there.
Come November in Indianapolis, those June miles will matter. But I prob won't be thinking about any of that when it's cold and raining at the start line.
