[--MAIN HOME--] [--ALL HABYHINTS--] RELATIVE HUMIDITY RIDDLE METEOROLOGIST JEFF HABY Riddle: The temperature is 110 F in Las Vegas. What does the dewpoint need to be in order for the relative humidity to be 5%? Answer to Riddle: The relative humidity has the formula of RH = (e/es)*100% 110 F = 43.33 C es can be found by using the Classius-Clapeyron equation LN(es/6.11) = 5321.0415*(1/273 - 1/T) T = 43.33 C = 316.33 K es = 6.11*e^(5,321.041215*(1/273 - 1/316.33) es = 88.21 mb Next, solve of e using RH equation 5 = 100e/88.21 e = (5*88.21)/100 = 4.4105 mb Next, use Classius-Clapeyron equation to solve for dewpoint LN(e/6.11) = 5,321.041215*(1/273 - 1/Td) LN(4.4105/6.11) = 5,321.041215*(1/273 - 1/Td) -0.325938711 = 5,321.041215*(1/273 - 1/Td) -0.325938711 / 5,321.041215 = (1/273 - 1/Td) -0.000061255 = (1/273 - 1/Td) -0.000061255 - 1/273 = -1/Td -0.003724258 = -1/Td 0.003724258 = 1/Td Td = 1/0.003724258 Td = 268.5 K = -4.5 C = 24 F