metpy.calc.heat_index(temperature, rh, mask_undefined=True)[source]

Calculate the Heat Index from the current temperature and relative humidity.

The implementation uses the formula outlined in [Rothfusz1990]. This equation is a multi-variable least-squares regression of the values obtained in [Steadman1979].

  • temperature (pint.Quantity) – Air temperature
  • rh (array_like) – The relative humidity expressed as a unitless ratio in the range [0, 1]. Can also pass a percentage if proper units are attached.

pint.Quantity – The corresponding Heat Index value(s)

Other Parameters:

mask_undefined (bool, optional) – A flag indicating whether a masked array should be returned with values where heat index is undefined masked. These are values where the temperature < 80F or relative humidity < 40 percent. Defaults to True.

See also