A general Nusselt number correlation is presented for transverse cylinders in subsonic and supersonic air flows where dissociation is negligible. New and existing data in the following experimental range have been correlated: Mach M = 0.001 to 6.0, Reynolds NRe = 0.02 to 300,000, Knudsen NKn = 4 × 10−6 to 37. In subsonic flow, heat transfer from a cylinder yawed at an angle to the air velocity is predicted by the transverse cylinder Nusselt number correlation when the normal velocity component is used as the characteristic velocity. Finally, recovery temperature data from cylinders are divided into three regimes by a Knudsen number criterion.