Runners: calculate exactly how much the summer heat is slowing you down

Temperature Calculator for Runners

Beat the heat this summer with this nifty calculator.

Now that the weather is starting to get hot, I am feeling a slight bit of frustration about my running pace. Although this happens to me every summer, the feeling that my pace isn't improving is uneasy. I need to actively remind myself that it is normal to run slower in the heat.


Just yesterday I was out on a run and I felt like I am keeping a great pace but when I looked at my GPS watch, my pace was significantly slower than it used to be. While this was initially a frustrating feeling, I needed to keep in mind that as the temperature outside is heating up it is going to have an inverse effect on my running pace.


The same pace feels harder on a hot day than on a cooler one

In other words, as the temperature rises, we are going to run slower for the same perceived level of exertion. Or the same pace feels harder on a hot day than on a cooler one. This is one of the reasons I advocate scheduling your runs for time and not for distance (more on that in a future post however…).


When I was out on my run in the 30 degree heat here in Edmonton, feeling like a slowpoke every time I glanced at my watch, I remembered an online temperature calculator at Runners Connect which I had seen over the winter.


I decided to plug my numbers into the calculator and saw that without the heat my pace was actually on par with my normal pace.


However, the calculator, which by the way  was developed by the founder of Running Connect, Jeff Gaudette, and legendary running coach Jack Daniels, has an even better use.


Use the temperature calculator before a run to adjust your pace

It's even better to use it before you go out for the run to adjust your pace. From the website:


Use this calculator on your workout days to adjust your goal pace according to the weather outlook. All the temperatures are for the “feels like” temperature, which takes into account both heat and humidity. For example, if you have a 10k tempo run scheduled, simply calculate how long it will take you to finish the entire run (i.e., if you’re running 6 minute pace, your total time would be a 36 minute 10k). Plug in your time and see how much you should adjust your pace for the given temperatures.


Try it, it will make your training more enjoyable this summer by managing your expectations of what you consider to be a good run.


About the author

Photo of Mira Toth, Waterloo Physiotherapist


Mira Toth, MScPT is a physiotherapist at PhysioMira Physiotherapy in Waterloo, Ontario. She has a Masters of Science in Physical Therapy from the University of Alberta, and has been practicing physiotherapy since 2008.

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