Maintaining an exercise routine during the warmer months of the year can be tough. With the sun beating down and the humidity cranked all the way up, even the most modest workouts can leave you feeling exhausted and sluggish. If you’re a daily distance runner, there’s a good chance you’ve noticed yourself slowing down with the onset of summer. And while it can be tempting to try to push through the pain, it’s important to appreciate just how much heat impacts the body.

To that end, RunnersConnect has created a Temperature Calculator to show you how temperature changes a workout. Simply input distance and time, and the calculator will tell you how rising heat will affect your run time down to the second. The calculator uses 60°F as the default temperature, so if you’re running a 10-minute mile, it will tell you how much that time will change at 65°F, 70°F, 85°F, and so on.

While increases in temperature will only change your mile run time by a few seconds on average, for long-distance runners, those few seconds can add up to minutes pretty fast. In general, the calculator is a handy tool for runners trying to stick to specific time goals, or for those who are interested in seeing how the heat might change their race performance. But it also serves as a reminder that even the best athletes can only do so much to beat the heat. 

[h/t Lifehacker]