Relative Humidity

Relative humidity, abbreviated as RH, a dimensionless number, is a measure of the amount of moisture in the air with respect to the temperature.

 

Relative Humidity formula
\(\large{ RH = \frac{e}{e_s} \;100 }\)
Symbol	English	Metric
\(\large{ RH }\) = relative humidity	\(\large{dimensionless}\)
\(\large{ e }\) = actual vapor pressure	\(\large{\frac{lbf}{in^2}}\)	\(\large{Pa}\)
\(\large{ e_s }\) = saturated vapor pressure	\(\large{\frac{lbf}{in^2}}\)	\(\large{Pa}\)

 

Relative Humidity formula
\(\large{ RH = 100 \;  \left(  \frac{ 112 \; - \; 0.1 \; T \; + T_d }{ 112 \; + \; 0.9 \; T }   \right)^8   }\)
Symbol	English	Metric
\(\large{ RH }\) = relative humidity	\(\large{dimensionless}\)
\(\large{ T_d }\) = dewpoint	\(\large{F}\)	\(\large{C}\)
\(\large{ T }\) = temperature	\(\large{F}\)	\(\large{C}\)