With the help of legendary running coach Jack Daniels, I’ve created an online calculator that will help you plan and account for exceedingly hot temperatures during workouts or on Race Day.
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.
You can also use this calculator to see how much your race time was affected by the heat. Plug in your finishing time and then subtract the new finishing time for the given temperature to see how well you would have finished if the weather had been perfect.
As with any calculator, please be aware that this is formula for the average person. Individuals respond differently to the heat and some might be more or less affected than others on hot days. Enjoy!
A few notes:
1. The first time you use the calculator, everything will be blank. Select a distance from the drop-down menu and the calculator will populate itself.
2. Enter your time as h:mm:ss. So, a 54 minute 10k time would be written as such – 0:54:00. You must include the first 0 if you ran under 1 hour.