 A simple colour correlation temperature fit gives temperatures around 3,749 K, while a full spectrum fit gives a temperature of 5,018 K. At a luminosity of , the size at its coolest has would be as large as compared to a smaller radius of at the hottest.The distance to RW Cephei has been estimated on the basis of its spectroscopic luminosity and is assumed to be a member of the Cepheus OB1 association at 3,500 parsecs, consistent with the parallax from Gaia Data Release 2.The temperature intermediate between the red supergiants and yellow hypergiants, and itself varying considerably, has led to it being variously considered as a red hypergiant or yellow hypergiant.