:thumbsup:
OK...I was just wondering because 62/82 is right at 75%, and I wasn't sure since you mentioned that if Tdew = 82, then that would be 100% humidity, and I thought you might be implying (82/82 = 100%).
So, we're on the same page. The formula above is an approximation, but it'll get us close enough. But, for those of us that think in Fahrenheit and not Celsius, it would be:
RH = 100 - 2.8(T-Td) ....
or since that would come closer to requiring a calculator ... we could probably get away with
RH = 100 - 2.5(T-Td)
for relative humidity values over 70% or so without introducing too much error....