Pace Calculator: Heat & Humidity
Are You Running the Right Pace for Today's Weather?
We're runners based in Atlanta—home to heat, humidity, and hills. So we spend a lot of time thinking about how the weather affects our training. Maybe you do too.
On hot and humid days, trying to hit your normal training pace can turn an easy run into a workout—or a controlled long run into a grind. Slowing down doesn't necessarily mean you're working less. Sometimes it's exactly what you need to do to get the right training effort.
Enter the pace you'd normally run in good conditions, along with today's temperature and humidity. We'll estimate your heat-adjusted pace—the pace that should produce a similar effort in today's weather.
Run the right effort, not just the number on your watch.
About This Calculator & the Research Behind It
This calculator is based on published research examining the effects of weather on endurance running performance. The researchers analyzed 7,867 athletes across 1,258 endurance races in 42 countries, comparing race performance with environmental conditions including temperature, relative humidity, wind speed, and solar radiation.
For this calculator, temperature and relative humidity are used to estimate simplified Wet Bulb Globe Temperature (sWBGT), a measure of environmental heat stress.
The simplified WBGT calculation is:
We then apply the study's published marathon performance relationship to estimate how much today's conditions may affect running pace relative to optimal conditions:
The calculator compares the predicted performance at today's estimated sWBGT with the minimum point of the study's performance curve. That difference is then applied to your normal running pace to estimate a pace that should produce a similar effort in today's conditions.
This calculator provides an estimate, not an individualized physiological prescription. The underlying study primarily reflects competitive endurance race performances, and this calculator applies the study's marathon performance relationship to training pace.
Individual responses to heat and humidity vary. Heat acclimation, direct sunlight, wind, workout duration, hydration, fitness level, and other individual factors can affect your actual running pace.