Function to calculate absolute humidity in grammes per metre³ given temperature in ° K, saturation vapour pressure in Pascals, and relative humidity as a percentage (0…100).

Compute actual vapour pressure.

Constants used in humidity calculations.

Central resolver function for humidity calculations

Function to compute the dew point, in ° Celsius, given temperature in ° Celsius and relative humidity percentage.

Function to return relative humidity.

Saturation vapour pressure function

Utility functions for humidity calculation

In computing the relative humidity of air after it has warmed, I need to account for the change in volume. By Charles’ Law, given stable pressure, volume is proportional to absolute temperature (i.e. V=Tk, where K is a constant). However, the sources I have read do not give that constant, for air. But seeing what I’m interested in is that amount of air which is contained in a cubic metre at standard temperature and pressure, then I think I can just take (temperature-kelvin/celsius-offset) as the temperature component.

Function to calculate wet bulb temperature (in ° C) given temperature in ° C and relative-humidity percentage (0…100)