Ambient temperature and altitude are used to determine design points for helicopters. In this paper, pressure altitude is used to determine the probabilities of Hover Out of Ground Effect HOGE capability rather than geophysical elevation. This strategy is applied to the state of Colorado. First this paper displays variations between geophysical elevation and pressure altitude. Then it shows that substituting pressure altitude for elevation leads to more conservative estimates for the HOGE capability. It is concluded that modern computational resources can be used to tailor helicopter design points to expected areas of operations rather than specifying a single generic temperaturepressure altitude combination.