Heat Index Calculator

NOAA heat-index regression.

Choose humidity inputCalculate heat index from relative humidity or derive humidity from dew point.

2 options

Air Temperature

°F

Relative Humidity

Temperature unit

Result unit

HEAT INDEX99.677718 °F

NOAA/NWS decision procedure at 60.00% relative humidity; simple formula below the regression threshold with official humidity adjustments.

Estimate based on the values shown

Formula checkedNOAA heat-index regression; dew point is converted to relative humidity with the Magnus equation. Temperature inputs and results may independently use °F or °C.

KEEP GOING

Useful next steps

◷TimeHours converted to minutes plus minutes→◎ConversionKilometers converted to miles→◷Date DifferenceDifference between day indices→