Relative Humidity
The equation below approximates the relative humidity within 0.6 percent in the range of -25 to 45 o C or -13 to
113o F. This is the equation used in the javascript calculator.

relative humidity equation

T is equal to the air temperature in degrees Celsius.

Td is equal to the dew point temperature in degrees Celsius.
To convert from Fahrenheit to Celsius use,
  • Celsius = (fahrenheit_temperature_value - 32) * 0.556

To conver from Celsius to Fahrenheit use,

  • Fahrenheit = 1.80 * celsius_temperature_value + 32.0 is the U.S. government's official web portal to all federal, state and local government web resources and services.