Heat and humidity pace calculator
How much should you slow down in Bangkok's heat? Adjust your running pace for temperature and humidity using dew point, with one-tap Bangkok presets.
How it works
Humidity matters because it stops sweat evaporating. The calculator turns temperature and humidity into a dew point, then adds temperature and dew point (both in °F) into a heat score, after coach Mark Hadley.
Score up to 100: no adjustment. Above that, the slowdown grows — about 1% per 10 points from 120–130, and faster beyond. Over 180, hard running isn't recommended at all.
A typical Bangkok morning (28°C, 80% humidity) scores around 158: expect to run roughly 5–6% slower than in cool weather.
FAQ
How much slower should I run in Bangkok?
On a typical humid morning, about 4–6% slower than your cool-weather pace; on hot-season afternoons, much more — or don't do hard sessions at all.
Is dew point better than humidity?
Yes. Relative humidity changes with temperature; dew point tells you how much moisture is actually in the air, and so how well sweat can evaporate.
Will I get used to the heat?
Mostly. Heat acclimatisation takes about 10–14 days of regular running in the heat, and improves sweating and heart-rate control, but you'll still be slower than in cool weather.
Results are estimates for planning training, not medical advice.