This text document is provided in the event a user has neither MS Works nor MS Excel available. It provides text and formulae for you to compute the dew point temperature when air temperature and relative humidity (RH) are known (or can be estimated).

Enter Temperature (F): __________

Convert to Temperature (C): Tc=5/9*(Tf-32) = __________

Calculate saturation vapor pressure (Es): Es=(6.11*10)^(7.5*Tc/(237.7+Tc)) = __________

Calculate actual vapor pressure (E) using RH and Es: E=(RH*Es)/100 = __________ (equals relative humidity expressed as %)

Finally, calculate the dew point temperature (Tdc) as follows:
Tdc= (-430.22+237.7*ln(E))/(-ln(E)+19.08) = ___________ (ln(E) means to take the natural log of the variable in parentheses)

Convert Tdc to Tdf : Tdf=(9/5)*Tdc+32 = __________

For this document I have used the caret (^) to represent exponentiation rather than the less common double-star (**).

Equations and constants obtained from USA Today Online