Weather-Adjusted Pace
At 30°C with high humidity, the same pace costs you far more than on a cool morning. Enter your pace and your city, and see how much slower to run based on the forecast, and which is the coolest hour over the next 7 days.
Works for any city, in Greece or anywhere in the world.
Pick a day and time
- Ideal
- Slightly warm
- Warm
- Very hot
- Dangerous
- Coolest hour
* An estimate, not medical advice. Everyone handles heat differently, and your body adapts within 10–14 days of training in the heat. If you feel dizzy or nauseous, or you stop sweating, stop at once, find shade and drink water.
Weather data: Open-Meteo.com (CC BY 4.0)
How it works
Heat alone does not tell the whole story. What cools your body while you run is sweat evaporating, and the more moisture there is in the air, the harder that gets. That is why this tool looks at temperature and dew point together; the dew point shows how much water the air actually holds.
It uses a practical rule many coaches apply: add the temperature and the dew point in degrees Fahrenheit. Up to 100, nothing changes. Above that, your pace slows gradually, up to about 10% when the sum reaches 180. Beyond that, hard running is not recommended. It is a rule from practice rather than an exact formula, but it agrees with studies showing that marathon times get steadily worse as temperature rises, and more so for slower runners.
To learn more about what happens to your body in the heat, read the article on cardiac drift.
Sources
The science behind this tool:
- Ely, M. R., Cheuvront, S. N., Roberts, W. O., & Montain, S. J. (2007). Impact of weather on marathon-running performance. Medicine & Science in Sports & Exercise, 39(3), 487–493. PubMed →
- Ely, M. R., Martin, D. E., Cheuvront, S. N., & Montain, S. J. (2008). Effect of ambient temperature on marathon pacing is dependent on runner ability. Medicine & Science in Sports & Exercise, 40(9), 1675–1680. PubMed →
- Racinais, S., et al. (2015). Consensus recommendations on training and competing in the heat. British Journal of Sports Medicine, 49(18), 1164–1173. PubMed →