Running BrowserRunning Browser · Models and assumptions
Temperature is part of the context of a run
Comparing a warm run with a mild one needs some care. Running Browser offers a temperature adjustment while keeping the recorded pace visible.
What the calculator actually uses
The default ideal-pace model adds a modeled time cost of 0.3% per degree Celsius above 22°C. Below 5°C it uses 0.2% per degree. Temperatures inside that range add no modeled temperature cost.
These are the existing application defaults, not universal physiological thresholds. Account settings can change where heat and cold begin to count.
What temperature alone cannot describe
Humidity, direct sun, acclimatization, clothing, duration and individual responses are not inputs to this simple temperature calculation. Two runs with the same reported temperature may feel quite different.
The result is intended for retrospective comparison. It does not determine safe conditions or tell you to hold a particular pace in heat.
Read the right model
The effort model described in the science book is configurable and differs from the ideal-pace model used by the public calculator. A percentage added to an effort score is not automatically the same percentage to subtract from pace.
Use the weather calculator to explore the ideal-pace estimate, and keep the original activity, conditions and notes together in your log.
Background reading
These references are also cited in the full science book. They provide background, not independent validation of the app’s estimates.
- Ely, M.R. et al. (2007). Impact of weather on marathon-running performance. Medicine & Science in Sports & Exercise. Reference 8 in the book
Keep the plan and the run together
Use the free training log and planner. Create an account to save your running across devices, then connect Strava from Settings → Integrations.
Create a free account Try the training planner