Dew Point & Heat Index
Comfort temperature from temp and humidity.
Dew point is the temperature where air is fully saturated. It's a more honest comfort signal than relative humidity because it doesn't change with temperature. The Magnus-Tetens formula is the standard approximation. Heat index uses the NWS Rothfusz equation and only applies when the temperature is at least 80°F.
About
Enter the air temperature and relative humidity. Get the dew point (a more honest comfort signal than RH alone) and the heat index (NWS feels-like temperature when it's hot). Handy before mowing the lawn or going for a run.
How to use
- Enter temperature and humidity.
- Read dew point and heat index.
FAQ
Why is dew point a better comfort metric than humidity?+
Relative humidity changes with temperature. Dew point doesn't, so 70°F dew point feels sticky no matter the air temp. Most meteorologists prefer it.
Why does heat index sometimes show a value lower than the input temp?+
It only applies when the temperature is at least 80°F. Below that, the formula isn't valid and the tool returns the temperature itself.